Positive charge
positive charge [1] On the contrary, we rub the fur rubber The charge on the rod is called negative charge 。 Charge is one of the three "properties" of matter: charge property, mass property and energy property. Charge is matter energy The result of interaction and transformation between quality and quality. Is matter Basic interaction One of the subjects of. The law of interaction between charges: the same kind of charges repel each other, and the different kinds of charges attract each other.
The difference between positive and negative charges: the material losing electrons is positively charged, and the material obtaining electrons is negatively charged.
Positively charged Nucleus stay Condensed matter It only vibrates in place, negatively charged Electronics Free movement. positive charge directional The direction of movement is the direction of current.
Negative charge means that the electron (with negative charge) is movable, while positive charge is actually an immovable proton
Around 600 BC, the Greek philosopher Thales (640-546B.C.) recorded that after rubbing cat hair on amber, amber would attract light objects such as feathers. If the rubbing time was long enough, even sparks would appear.
In 1600, the British doctor William Gilbert made a very careful study of electromagnetic phenomena. He pointed out that amber is not the only material that can generate static electricity through friction, and distinguished Electricity and magnetism Different properties. He wrote the first scientific book on electricity and magnetism, On Magnets. Gilbert created the new Latin term "electricus" (similar to amber, from“ ήλεκτρον”， "Elektron", "amber" in Greek, means the nature of attracting small objects after friction. This connection gives the English words "electric" and "electricity", which first appeared in 1646, Thomas Browne (Thomas Browne)'s work Pseudotoxiia Epidemica (English title: Enquiries into Every Many Received tenets and Commonly Preserved Trusts) followed by, in 1660, scientists Otto Von Guericke Invented, probably the first book in history Electrostatic generator (electrostatic generator)。 He will sulfur The ball is fixed on one end of an iron shaft, and while rotating the sulfur ball, rub the sulfur ball with dry hands to make the sulfur ball generate electric charges and attract small substances. Stephen Gray (Stephen Gray) discovered electric conduction in 1729. Electric charge can be transferred from one substance to another. Only some substances conduct electric charges, of which metal is the best. From then on, scientists no longer believed that the object generating the charge was inseparable from the generated charge, but that the charge was an independent substance, which was called Current body (electric fluid)。 In 1733, Charles du Fay (Charles du Fay) divides electricity into two types, Glassy electricity and Amber electricity 。 These two kinds of electricity will cancel each other out. When the glass rubs against the silk towel, the glass will generate glass electricity; When amber rubs with fur, amber generates amber electricity. This theory is called Two fluid theory of electricity 。 Using a charged wire, we can know whether the substance has glass electricity or amber electricity. Materials with glass electricity will repel charged wires; Materials with amber electricity will attract charged wires.
In the 18th century, Benjamin Franklin was the leading expert in electricity. He thinks Single fluid theory of electricity Quite right. He imagined that electricity was stored in all substances, and usually Equilibrium state The friction action will make electricity flow from one object to another. For example, he believes that the accumulated electricity is stored in Leiden bottle Rub the glass with a silk towel to make electricity flow from the silk towel to the glass. This flow formed electric current 。 He suggested Electricity An object that is below balance carries a negative charge, and an object that is above balance carries a positive charge. He arbitrarily set the glass electricity as positive, with excess electricity; Amber electricity is negative and lacks sufficient electricity. At the same time, William Watson reached the same conclusion. In 1747, Franklin assumed that in an isolated system Charge quantity Constant, which is called Law of conservation of charge 。 Coulomb Torsion scale (torsion balance) In the late 18th century, the research on electricity began to have substantial development in terms of quantity. 1785, used Charles Coulomb And Joseph Priestley Independently invented Torsion scale Coulomb confirmed the basic law of Priestley: the force felt between two objects with static charges is inversely proportional to the square of the distance. This lays the foundation of static electricity Laws 。 In 1897, University of Cambridge Cavendish Laboratory Of Joseph John Thomson Observed Cathode ray It will deflect due to electric or magnetic fields. He deduced that cathode rays are composed of negatively charged particles, later called electrons. From the deflection of the cathode ray, he calculated the Charge mass ratio Therefore, we obtained the The nobel prize in physics 。 In 1904, Thomson founded atom Of Plum pudding model The structure of the atom is analogous to plum pudding, where the negative charge (plum) is dispersed in a positively charged sphere (pudding). This model is Ernest Rutherford Of Rutherford scattering The experiment was overturned in 1909. Rutherford also proposed Rutherford Model : Most of the mass and positive charge are concentrated in a small area（ Nucleus ）； The electrons are surrounded outside the nuclear region. In 1909, American physicist Robert Milligan He did a famous experiment called Oil drop experiment , can accurately measure the amount of electronic charge. Thomson and students John Townsend (John Townsend) Use electrolysis The ionic gas of Supersaturation Water vapor condensation, after measuring the Charge quantity Similar results are obtained. In 1911, Abram Joffe (Abram Ioffe) Using charged metal particles, the same results can be obtained independently. There is a sudden change on the interface between monocrystalline silicon and amorphous silicon dioxide. In silicon dioxide molecule, each silicon atom is bonded to four oxygen atoms, and each oxygen atom is bonded to four silicon atoms. However, on the Si/SiO2 interface, as shown in the figure below, some silicon atoms are not bonded to oxygen atoms, resulting in some silicon atoms becoming acceptors. Therefore, the incomplete oxidation of silicon within 2nm from the Si/SiO2 interface is a positive fixed oxide charge area. Other charges accumulated at the interface include interface trap charges and movable oxide charges. The interface trap charge is mainly composed of positive or negative charges caused by structural defects, oxidation induced defects or metal impurities; The movable charge is mainly caused by the contamination of movable ions [2] 。
These positive charge accumulation layers stacked at the interface will induce corresponding negative charges in the silicon substrate, and these negative charge layers will form conductive channels between the two N+strips, thus reducing the inter strip resistance and adversely affecting the charge collection of the detection strip. In this regard, B ions can be implanted between two N+strips to form P+strips. In this way, the P+bars between two adjacent N+bars and N+bars are in reverse offset, effectively blocking the surface channel between bars. This technology is called P-stop technology [2] 。
Positive charge accumulation layer
