CMOS is the abbreviation of Complex Metal Oxide Semiconductor.It refers to manufacturing large-scaleIntegrated circuit chipA technology used or a chip manufactured by this technology is a readable and writable piece on the computer motherboardRAMChip.Because of the read-write featureComputer motherboardUsed to save BIOS settings onComputer hardwareThe chip is only used to store data after parameters.
The setting of various parameters in BIOS should be done through special procedures.BIOSThe setup program is generally integrated into the chip by the manufacturer. When starting up, you can enter the BIOS setup program through a specific key to facilitate the system setup.Therefore, BIOS settings are sometimes called CMOS settings.
In the computer field, CMOS usually refers to the chip that stores the basic computer startup information (such as date, time, startup settings, etc.).Sometimes people confuse CMOS and BIOS. In fact, CMOS is a read/write parallel or serial piece on the motherboardFLASH chip, is used to saveBIOSOfhardware configurationAnd user settings for certain parameters.
In addition,CMOS can also refer to complementary metal oxide half components and processes。
So up to now, although they are all called CMOS for process reasons, there are three types of CMOSapplication area , showing completely different appearance characteristics:
First, it is used to save computer information. CMOS is used as a rewritable chip. In this field, users usually do not care about CMOS hardware problems, but only about the information written on CMOS, that is, BIOS settingssystem failure Remove the battery on the motherboard and discharge the CMOS to restore the BIOS settings.
Second, indigital image As a low-cost sensor technology, CMOS has been developedElectronicsAnd its photosensitive elements are mainlyCCDOr CMOS, especially low-end camera products, while high-end cameras are usuallyCCD sensor。
If compatibleDesktop computer, and it is the BIOS setup program of Award, AMI and Phoenix, then pressDelete keyorKeypadYou can enter the CMOS setting interface by pressing the Del key on the.
If it isBrand machine(including desktop computers orNotebook computer）If you can't enter CMOS by pressing Delete, you should see the prompt on the computer screen after starting up. Generally, [Press XXX to Enter SETUP] appears, and then we can press the "XXX" key to enter CMOS.The trigger key of the notebook is generally F2 or Delete.
If there is no prompt, check thean instruction manual。If you can't find them, try the following keys commonly used by brand computers:
“F2”，“F10”，“F12”, "Ctrl+F10", "Ctrl+Alt+F8", "Ctrl+Alt+Esc", etc.
Setting method
1、 Enter the CMOS setting interface
After turning on or restarting the computerScreen displayWhen "Waiting...", press the "Del" key to enter the CMOS setting interface.Note that if you press too late, the computer willStarting the system, you have to restart your computer.You can press and hold the Del key immediately after startup until you enter CMOS.After entering, you can useDirection keymovecursorSelect the option on the CMOS setting interface, and then press Enter to enter the subMenu。
2、 Set date
We can modify the computer time by modifying the CMOS settings.Select the first standard CMOS Setup and press Enter to enter the standard setting interface. The format of the date in CMOS is<;;Week><;;Month><;;Date><;;Year>;;,Except that the week is calculated by the computer according to the date, others can be entered by moving the cursor in turn with the number keys. If today is June 1, you can change it to June 2.Of course, you can also use Page Up/Page DownTo modify.
3、 Set startup sequence
If we want to install a new operating system, we generally need to change the starting sequence of the computer tofloppy disk(A) Boot or CD（CD-ROM）Start.Select the second option BIOS Features Setup in the CMOS main interface, move the cursor to the boot sequence item, and then use PageUp or PageDown to select modification, where A means to change fromFloppy startup, C means boot from hard disk, CD-ROM means boot from CD,SCSIIt means to start from the SCSI device. The startup order is determined according to its order. The first one starts from the first one.For example, C:CDROM, A, means to start from the hard disk first. If the hard disk cannot start, start from the CD. If both the hard disk and the CD cannot start, start from theA diskStart.In BIOS feature settings, there are several important options:
① Quick Power On Self TestPOST）, when the computer is powered on,a main boardThe BIOS will perform a series of checks and tests to check the system andPeripheral equipment。If Enabled is selected, the BIOS will simplify the self-test steps to speed up power on.[1]
② Boot Up Floppy Seekfloppy disk driveCheck), when the computer is powered on, the BIOS will check whether the floppy drive exists.When Enabled is selected, if the BIOS cannot check the floppy drive, it will prompt the floppy drive error.If you select Disabled, the BIOS will skip this test.
③ Boot UP NumLock Status. Generally,Keypad(The right part of the keyboard) is used as a number key (the default is ON, and the enabled keypad is a number key). If there is a special need, just change ON to OFF, and the keypad will become a direction key.
④ Security Option
There are two options. If you set it to Setup, you do not need a password when starting up, but you need a password when entering CMOS (of course, you need to set a password in advance), but onlySuper userThe password of can only be used to change various CMOS parameters. The password of ordinary users cannot.If it is set to System, a password is required when starting up (both super user and ordinary user passwords can be used). When CMOS is modified, only super user passwords are availableRight to modify。
As the core of the computer, CPU has special settings in CMOS.In the main interface, use the arrow keys to move to "<<<CPU PLUG&PLAY>>>;;", and then we can set various parameters of the CPU.In "Adjust CPU Voltage", set theCore voltage。If you want to change this value, use the arrow keys to move to the item, and then use "Page UP/Page Down" or "+/-" to select the appropriate core voltage.Then use the arrow keys to move to "CPU Speed", and use "Page UP/Page Down" or "+/-" to select the applicable frequency multiplication andfsb 。Note that if there is no special need, beginners should not change the CPU related options at will!
5、 Set Password
CMOS provides users with two password settings, namely super VI SOR/USER PASSWORD.The password setting method is as follows:
1. Select "SUPER Ⅵ SOR PASSWORD" in the main interface, press the Enter key, and the Enter Password appears,
2. The password you entered cannot exceed 8 characters, and the screen will not display the entered password. PressEnterKey,
3. At this time, you will be asked to confirm the password: "Confirm Password". Enter the password you just entered to confirm, and then press Enter to set it.
The common user password is the same as its settings, so it is no longerSay moreHas.If you need to delete your previously set password, just select this password and press Enter (do not enter any characters), so you will delete your previously set password.The difference between the passwords of super users and ordinary users is that when entering CMOS, entering the password of super users can modify all the options of CMOS, while ordinary users can only change the password of ordinary users, and cannot modify other parameters in CMOS. The contact is that when the security option is set to SYSTEM, entering any of them can power on.
6、 Set hard disk parameters
If you want to replace the hard disk, you need to set the hard disk parameters in CMOS after installing the hard disk.CMOS has the option of automatically detecting hard disk parameters.Select the "IDE HDD AUTO DETECTION" option in the main interface, and then press the Enter key, CMOS will automatically find the hard disk parameters and display them on the screen, where SIZE isHard disk capacity, inMB；MODE is the hard disk parameter, the first is NORMAL, and the second isLBAThe third is LARGE.We type "Y" on the keyboard and press Enter to confirm.
Next, the system detects the remaining threeIDE interfaceIf it is detected, it will be displayed. You just need to select it.After detection, it will automatically return to the main interface.At this time, the information of the hard disk will be automatically written into the first option of the main interface - STANDARD CMOS SETUP.
7、 Save Settings
All the changes we have made must be saved before they take effect. Otherwise, all our previous efforts will be wasted.After setting, press ESCReturn to the main interface, move the cursor to "SAVE&E XI T SETUP" (store and end setting) to save (or press F10), press Enter, select "Y", and it is OK.
Parameter setting
If CMOS does not provide shutdown operation, software settings can be used as follows:
⒌PnP/PCI Configuration Setup：Plug and PlayAnd PCI plug-in parameter settings.
6. Integrated Peripherals: integrate the settings of peripherals.
7. Others: hard disk automatic detection, system password, loading default settings, exiting, etc
Battery discharge
Open the main box of the computer, you can see a "round" flat battery on the right side of the motherboardButton cell Also calledcmos battery , save mainboard informationBIOS settingsWhen I work in an Internet cafe, I often encounter the situation that the host can not be started. Generally, the easy way to work is to unplug the host, which meanspower cordRemove it from the power box, which is completely powered off. Remove theThe button batteryTwo pieces of metal can be seen, forming up and down, that is, the positive/negative circuit. Connect them and make them short circuited. Press them for a few seconds, and the discharge is basically successful
Another is called small CMOS discharge: also, unplug the power cord from the power box, press the "Start" button in this state, and then try again. The system will also discharge slightly, which can generally solve the problem that the computer cannot be started
It is often heard that computer experts or non experts say, "Forgot the password? Discharge the CMOS." What does this mean?
If you set the access password in the computer, and you happen to forget the password, you will not be able to access the computer.Fortunately, the password is stored in CMOS, and CMOS must have power to keep the data in it.Therefore, we can make the computer "give up" the requirement of password by discharging CMOS.The specific operations are as follows:
Open the chassis, find the button battery on the motherboard, and disconnect it from the motherboard (that is, remove the button battery or adjust the jumper). At this time, the CMOS will lose all information stored internally due to power failure.Then connect the button battery, close the chassis and start the machine. Since the CMOS is blank, it will no longer require you to enter a password. At this time, enter the BIOS setup program and selectMain MenuLOADBIOSDEFAULT inDefault）Or "LOADSETUPDEFAULT" (the default value of the load setup program). The former starts the computer in the safest way, and the latter enables your computer to play a higher performance.
data recovery
Document CMOSThe contents of DAT can be displayed in DEBUG (orPCTOOLSAnd other tool software), you can alsoWritebackCMOS，Here is the program for automatically writing back data:
/*Put the A disk CMOSDAT fileWrite data back to CMOS*/
For various reasons, it is sometimes necessary to decode or destroy the CMOS password. At this time, different methods can be adopted according to the specific situation.If you can start the system, but cannot enter the CMOS setting state because you forget or do not know the CMOS password, you can useprocedural lawTo decode the CMOS password, use the program to destroy the settings of the CMOS password:
In the future, as long as you can use the floppy disk to start the system, run DELMOSCOM can cancel the setting of CMOS.
history
CMOS is readable and writable on the motherboardRAMThe chip is used to save the hardware configuration information of the current system and some parameters set by the user.CMOS RAM is powered by the button battery on the motherboard, and information will not be lost even if the system is powered off.The setting and updating of various parameters in CMOS can be realized by specific keys (generally Del key) when starting up.Enter BIOS setup program to set CMOS.Generally, CMOS settings are also called BIOS settings.
CMOS and BIOS
BIOS is a read-write part on the motherboardEPROMorEEPROMChip, which contains important information and settings of the systemsystem parameterSetup program of (BIOSSetup program);CMOS is a read-write RAM chip on the motherboard, which contains information aboutsystem configurationIts contents can be read and written through the setting program.The CMOS RAM chip is powered by a button battery, and the information will not be lost even after the system is powered off.CMOS RAM is not only the storage place for BIOS to set system parameters, but also the result of BIOS setting system parameters.
CMOS，That is: Complementary Metal Oxide Semiconductorstorage, is a large-scale application ofIntegrated circuit chipIt is a read-write RAM chip on the PC motherboard.The CMOS RAM chip is powered by the system through a button battery, so the CMOS information will not be lost whether the system is powered off or powered off.
BIOS is a set of computer programs for setting hardware, stored in an EPROM or EEPROM chip on the motherboard, which contains important system information and the setup program for setting system parameters - BIOS Setup program.CMOS, namely, Complex Metal Oxide Semiconductor, is a read-write RAM chip on the motherboard, which is used to save the current system hardware configuration and user's parameter settings. Its contents can be read and written through the setup program.CMOS chipIt is powered by the button battery on the motherboard. Even if the system is powered off, the parameters will not be lost.CMOS chip only has the function of saving data, and the modification of various parameters in CMOS must be realized through the BIOS setting program.CMOS RAM is not only the storage place for BIOS to set system parameters, but also the result of BIOS setting system parameters.Therefore, the complete statement should be "setting CMOS parameters through the BIOS setup program".Since BIOS and CMOS are closely related to system settings, the BIOS settings and CMOS settings are the same thing in practice.
BIOS is actually a microcomputerBasic input/output system(BasicInput Output System), its contents are integrated on a ROM chip on the microcomputer motherboard, which mainly storesmicro-computer systemThe most important basic I/O program,system information Setting and startupPower on self-testProgram and system startup self-test program, etc.
BIOS functions mainly include the following aspects:
First, BIOSInterrupt service program, that is, between software and hardware in microcomputer systemProgramming interface, which is mainly used to realize the connection between program software functions and microcomputer hardware.The management of peripheral devices such as floppy disk, hard disk, CD-ROM drive, keyboard and display by the operating system is directly based on the interrupt service program of the BIOS system. The operator can also access INT5, INT13, etcBreakpointInstead, directly call the BIOS interrupt service program.
BIOSSystem SetupAs mentioned earlier, the configuration record of microcomputer components is placed in a read-write CMOS RAM chip, which mainly stores the basic information of the system, CPU characteristics, softwareHard drive, display, keyboard and other components.The "System Setup" is installed in the BIOSROM chip, which is mainly used to set the parameters in the CMOS RAM.This program can enter the setting state by pressing a specific key when starting up, and provides a good interface for operators to use.In fact, this process of setting CMOS parameters is customarily called "BIOS setting".
ThirdPOST power on self-testProgram: After the microcomputer is powered on, the system first checks the internal devices by the POST (PowerOnSelfTest) program.Usually completePOST self inspectionWill include CPU, 640KBasic memory, 1M and aboveExtended memory, ROM, mainboard, CMOSmemory, serial and parallel portDisplay cardThe software and hard disk subsystem and keyboard are tested. Once problems are found in the self inspection, the system will give a prompt message or sound a horn warning.
The fourth is the bootstrap program for BIOS system startup. After the system completes POST self-test, ROMBIOS will first search the software and hard disk according to the startup sequence saved in the system CMOS settingsDriverAnd CD ROMNetwork serverStart the drive effectively, read the operating system boot record, and thencontrol powerIt is handed over to the boot record, and the boot record completes the smooth startup of the system.
CCD andCMOS image sensorphotoelectric conversion The main difference between them lies in the different readout processes of signals;Since CCD has only one (or a few) output nodes for unified readout, the consistency of its signal output is very good;In CMOS chips, each pixel has its ownsignal amplifier, and their signal output consistency is poor.However, in order to read the whole image signal, the CCD needs to output theSignal bandwidthWide, while in CMOS chips, eachpixel The low bandwidth requirement of the amplifier in the CMOS chip greatly reduces the power consumption of the chip, which is the main reason why the power consumption of the CMOS chip is lower than that of the CCD chip.Although the power consumption is reduced, millions of amplifiersInconsistencyBut it brings higher fixed noise, which is the inherent disadvantage of CMOS compared with CCD.
Integration
From the perspective of manufacturing process,CCDCircuits and devices are integrated in semiconductorsSingle crystal The process is complex, and only a few manufacturers in the world can produce CCDCrystal unit, such as DALSA, SONYPanasonicEtc.CCD can only outputAnalog electrical signal, subsequent addresses are requireddecoder, analog converter, imageSignal processorProcessing, and three sets of power supplies with different voltages are also requiredSynchronize clockControl circuit,IntegrationVery low.CMOS is integrated inmetallic oxideOfsemiconductor material On the other hand, this process can produce tens of thousands ofComputer chipandstorage deviceThe process of semiconductor integrated circuits is the same, so the cost of producing CMOS is much lower than that of CCD.At the same time, CMOS chip can transform image signal amplifier, signal reading circuitA/D conversion circuit, image signal processor and controller are integrated into one chip, and only one chip is needed to realize all the functions of the camerabasic function The integration is very high. This is where the concept of chip level camera came into being.With the continuous development of CMOS imaging technology, more and more companies can provide high-quality CMOS imaging chips, including Micron, CMOS IS, Cypress, etc.
3. Speed
CCD adopts photosensitive output one by one, which can only be output according to the specified program, and the speed is slow.CMOS is controlled by multiple charge voltage converters and row column switches, with much faster readout speedHigh speed cameraAll are CMOS cameras.In addition, the CMOS address strobe switch canRandom samplingTo achieve sub window output, higher speed can be achieved when only sub window images are output.
CCDtechnological development Early, relatively mature, PN junction or silicon dioxide (SiOtwo）Isolation layerNoise isolation, image quality relative to CMOSPhotoelectric sensorIt has certain advantages.Due to the high integration of CMOS image sensor and the close distance between components and circuits, the interference is seriousimage qualityGreat impact.With the continuous development of CMOS circuit noise elimination technologyhigh-densityHigh quality CMOS image sensor provides good conditions.
Integrated circuit
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CMOS can also refer to complementary metal oxide semiconductor and manufacturing process.Under the same functional requirements.
Since 1958, the United StatesTexasInstrument company（TI）InventionIntegrated circuitAfter IC, with the development of silicon plane technology, two important integrated circuits, bipolar and MOS, were invented in the 1960sElectronic tubeandtransistorThe era of manufacturing electronic complete machines has witnessed a leap in quantity and quality.
MOSYes: Metal-oxide-The transistor with semiconductor structure is called MOS transistor for short, which can be divided into P-type MOS transistor and N-type MOS transistor.The integrated circuit composed of MOS tubes is calledMOS integrated circuitByPMOS tubeThe complementary MOS integrated circuit composed with NMOS transistor isCMOS-IC（Complementary MOS Integrated Circuit）。
CMOS, the full name is Complex Metal Oxide Semiconductor, which is a large-scale application ofIntegrated circuit chipRaw materials for manufacturing.Coupled metal oxide semiconductor field effect transistors (MOSFETs) can be integrated on a silicon chip using CMOS technology.This technology is usually used for productionRAMAnd Exchangeapplication systemIn the computer field, it usually refers to the RAM chip that stores the basic computer startup information (such as date, time, startup settings, etc.).[2]
CMOS is composed of PMOS transistor and NMOS transistor, and its characteristics arelow power consumption。Because a pair of MOS in CMOSGate circuitAt the instant, either PMOS is on, NMOS is on, or both are off, which is more linear thantriode（BJT）The efficiency is much higher, so the power consumption is very low.
Relative to other logical series,CMOS logic circuitIt has the following advantages:
1. The allowable power supply voltage range is wide and convenientPower circuitDesign of
4、BarrierThe structure of the CMOS deviceInput resistanceExtremely, which enables CMOS devices to drive similar devicesLogic gateIs much better than other series
advantage
Relative to other logical series,CMOS logic circuitIt has the following advantages:
1. The allowable power supply voltage range is wide, facilitating the design of power circuit
2. Large logic swing makes the circuit have strong anti-interference ability
4. The isolation gate structure makes the input resistance during CMOS extremely high, so that the ability to drive similar logic gates during CMOS is much stronger than other series
CMOS developed later than TTL, but it gradually replaced TTL in many occasions with its higher advantages.
After comparing the performance of the two, we can see the reason.
outputHigh level>2.4V, outputLow level<0.4V。At room temperature, the general output high level is 3.5V, and the output low level is 0.2V.Minimum input high level and low level: input high level>=2.0V, input low level<=0.8V,Noise toleranceIt is 0.4V.
The 1 logic level voltage is close to the power supply voltage, and the 0 logic level is close to 0V.It also has a wide noise tolerance.
3. Level conversion circuit:
Because the high and low level values of TTL and CMOS are different (ttl5v<==>cmos 3.3v), level conversion is required when connecting to each other: that is, two resistors are used to divide the level voltage, and there is nothing profound.
4. Drive door circuit
OC door, i.eOpen collectorGate circuit, OD gate, i.e. open drain gate circuit, must be externally connectedPull up resistanceAnd power supply can use the switch level as the high and low level.Otherwise, it is generally used as a switch for high voltage andlarge currentLoad, so it is also called driving gate circuit.
The internal current of CMOS circuit increases sharply due to too large current input. The current increases all the time unless the power supply is cut off.This effect is the lock-in effect.When the locking effect is generated, the internal current of CMOS can reach more than 40mA, which is easy to burn the chip.
Defensive measures:
1) AddClamp circuit, so that the input and output do not exceed the specified voltage.
2) Power input terminal of the chipdecouplingCircuit to prevent instantaneous high voltage at VDD end.
3) OnVDDAnd external power supplyCurrent limiting resistor, even if there is a large current, it will not be allowed to enter.
4) When the system is powered by several power supplies respectively, the switch shall be in the following order: when it is turned on, the power supply of CMOS circuit shall be turned on first, and then the power supply of input signal and load shall be turned on;When turning off, first turn off the power supply of input signal and load, and then turn off the power supply of CMOS circuit.
6. Precautions for use of CMOS circuit
1) CMOS circuit is a voltage control device, and its total input impedance is very largeinterference signalThe ability to capture is very strong.Therefore, the unused pin shall not be suspended, and the pull-up resistor orPull down resistance, give it a constant level.
2) Input Termination Lowinternal resistanceOfsignal sourceThe current limiting resistor shall be connected in series between the input terminal and the signal source to limit the input current within 1mA.
4) When the input terminal is connected with large capacitanceProtective resistance。The resistance value is R=V0/1mAV0 is the voltage on the external capacitance.
5) If the input current of CMOS exceeds 1mA, it may burn out CMOS.
7. Input terminal in TTL gate circuitLoad characteristics(Handling of special cases of input terminal with resistance):
1) When suspended, it is equivalent to the high level of the input terminal.Because it can be regarded as an input terminal connected with aInfinityResistance of.
2) After the 2.5K resistor is connected in series at the input end of the gate circuit, the low level is input, and the input end presents a high level rather than a low level.Because it can be known from the load characteristics of the input end of the TTL gate circuit (based on the 74 seriesTTL inverterFor example, only when the series resistance connected to the input terminal is less than 910 Ω, the low-level signal it inputs can be recognized by the gate circuit, and if the series resistance is higher than 2.5K, the input terminal will always show a high level.This must be noted.CMOS gate circuits do not need to consider these.
8. Output processing of TTL and CMOS circuits
TTL circuit hasOpen collectorOC gate and MOS tube also have andcollectorCorrespondingOpen drainIts output is calledOpen drain output。OC gate has leakage current output when it is cut off, which is leakage current. Why does it have leakage current?That's because when the triode turns off, itsBase currentApproximately equal to0, but it is not really 0. The current passing through the collector of the triode is not really 0, but about 0.This is the leakage current.Open drain output: the output of OC gate is open drain output;The output of OD gate is also open drain output.It can absorb a large amount of current, but can not output the current outward.Therefore, in order to input and output current, it should be used in accordance with the power supply andPull up resistanceUse them together.OD gate is generally used as output buffer/Driver、Level converterAnd large absorptionload current Needs.
9. What isTotem poleWhat is the difference between it and open drain circuit?
In TTL integrated circuit, the output connected with pull-up triode is calledtotem pole output The one without is called OC gate.Because TTL is a three-level tube, and totem pole is a push-pull connection between two three-level tubes.So pushing and pulling is totem.General totem output, high level 400UA, low level 8MA
N-type with light doping in p-hydrazine CMOS processsubstratePrepare PMOS devices.In order to make N-type device, it is necessary to make P-hydrazine on N-type substrate first, and make NMOS device in p-hydrazine.
The typical P-hydrazine silicon gate CMOS process, from substrate cleaning to intermediate testing, has more than 50 processes in total, requiring 5 timesion implantation , together with the etching and passivation window, 10 times in totalPhotolithography。The following is combined with the maintechnological processThe forming process of elements in P-hydrazine silicon gate CMOS integrated circuits is introduced.
(1) Light 1 - photolithography of hydrazine area, marking the injection hole of hydrazine area.
(2) Hydrazine zone injection and promotion to form hydrazine zone.
(4) Light 2 - reverse etchingActive region(Photolithography field area), reverse engraving the source, drain and gate area of P tube and N tube.
(5) Light 3 - lithography N tube field area, cut the glue on N tube area, and expose the injection hole of N tube field area.N tube field injection to improve field opening and reduceLatch up effectAnd improve hydrazine exposure.
(7) Light 4 - photolithography P-tube area.P Tube area injection, adjust theOpening voltage, then longpolysilicon 。
(8) Light 5 - reverse etching of polysilicon to form polysilicon gate and polysilicon resistance.
(9) Light 6 - lithography of the P+area, cutting off the glue on the P tube and other P+areas.P+area injection, forming the sourceLeaky areaAnd P+Protective ring。
(10) Light 7 - Lithograph the N+area, and remove the glue on the N+area.The N+area is injected to form the source, drain area and N+protection ring of the NMOS tube.
(11) Long PSG
(12) Light 8 - photolithographic lead hole.Can growPhosphosilicate glassAfter that, first open the primary hole, and then open the second hole after the phosphorus silicon glass reflux and junction injection are advancedSecondary hole。
Early Split CMOSLogic elementOnly "4000 series"（RCA'COS/MOS' process). By the time of the later "7400 series", many logic chips can already use CMOS, NMOS, or evenBiCMOS(DoublecarrierComplementary metal oxygen half) process.
Early CMOS components and majorcompetitorBJT is very vulnerable toelectrostatic discharge (Electrostatic Discharge, ESD).And the new generationCMOS chipMost of the output and input pins (I/O pins) and power and ground terminals are equipped with ESDprotection circuit To avoid internalCircuit elementOf the grid or elementPN junction(PN Junction) is burned by a large amount of current caused by ESD.However, most chip manufacturers still warn users to use anti-static measures as far as possible to prevent semiconductor components from being damaged by energy beyond the capacity of ESD protection circuit, such as installationMemory modulereachpersonal computerUsers are usually advised to wear anti-static bracelets and other equipment when installing.
In addition, early CMOSLogic elementThe operating range (e.g. 4000 series) can range from 3 volts to 18 voltsDC voltageTherefore, the gate of CMOS components uses aluminum as the material.For many years, most of the logic chips made with CMOS also operated under 5 volts of TTL standard specifications. Until 1990, more and more low-power requirements and signal specifications appeared, replacing TTL, which has a relatively simple signal interface, but its power consumption and speed can not keep up with the needs of the times.In addition, as the size of MOSFET components becomes smaller and smaller, the thickness of the gate oxide layer becomes thinner and thinner, and the grid voltage that can withstand becomes lower and lower. Some of the latest CMOS processes have even seen operating voltages below 1 volt.These changes not only further reduce CMOS chipsPower consumptionAnd make the performance of components better and better.
Most modern CMOS gates are made of polysilicon.Compared with the metal gate, the advantage of polysilicon is that it has a wide temperature tolerance range, which makes the annealing process after ion implantation more successful during the manufacturing process.In addition, it is also possible to use self align when defining the grid area, which can reduce the grid area and further reduce theStray capacitance（stray capacitance）。After 2004, some new research began to use metal gates, but most of the manufacturing processes are still polysilicon gates.With regard to the improvement of grid structure, there are many studies focused on the use of different grid oxide materials to replacesilicon dioxide, such as using high dielectric coefficientDielectric material(high-K dielectrics) to reduce the gate leakage current.
Other abbreviations
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Research on Media Optimization
（Cross Media OptimizationStudy）
IAB's Internet Advertising Bureau has cooperated with well-known brands since 2003Advertisers, MediaMedia AgencyAnd other participants to jointly promote XMOS cross media optimization study to attractDove、McDonald's, Ford, ING and other brands, andGoogle,Yahoo,AOL, MSN, cnet and other media.
IAB in the UK, EuropeAustraliaetc.Internet advertisingThe synchronous promotion of more mature countries has formed very effective guidance and help for improving the ROI of advertising.
Dynamic Logic, a research company, has also promoted cross media research in the US market, including TV, Internet, flat media, outdoor and other media evaluations, to help advertisers optimize media and marketing methods.
Relevant technical terms
one
complementary metal oxide semiconductor (CMOS）Complementary metal oxide semiconductor
two
Silicon-on-insulatorCMOSSilicon insulatorCMOS
three
High speedCmosWith TTL thresholds (as in 74HCT245)CMOSDevice (if 4HCT245)
four
High speed Complex Metal Oxide SemiconductorCMOS
five
Bipolar-CMOS-DMOS bipolar complementary metal oxide semiconductor double diffusion metal oxide semiconductor
six
AdvancedCMOSLogic (as in 74ACL245) AdvancedCMOSLogic (e.g. 74 ACL245)
