Metal-Insulator-Semiconductor MIS Junction

In the case of negative bias, the Fermi level moves closer to the valence band edge. Consequently, the concentration of the majority of carriers (holes) at the insulator-semiconductor interface becomes larger than in the bulk. This corresponds to the accumulation regime. When a positive bias is applied to the metal. 

To solve this differential equation, we introduce the electric field F  

Substituting the far right term of (14.14) into the left hand side of (14.12) yields a differential equation that can be integrated with respect to V, leading to  

the sign of the right hand side equals that of the applied bias. The total charge in tlie semiconductor, Q, is related to the electric field at the insulator-semiconductor interface, F, according to Gauss s law  

The variation of the absolute surface charge as a function of surface potential (in linear-log scale) is shown in Eigure 14-5. 

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Contacts are the elementary building blocks for all electronic devices. These include interfaces between semiconductors of different doping type (homojunctions) or of different composition (heterojunctions), and junctions between a metal and a semiconductor, which can be either rectifying (Schotlky junction) or ohmic. Because of their primary importance, the physics of semiconductor junctions is largely dealt with in numerous textbooks [11, 12]. We shall concentrate here on basic aspects of the metal-semiconductor (MS) and, above all, metal-insulator-semiconductor (MIS) junctions, which arc involved in the oiganic field-effect transistors. 

CdSe particulate films could be transferred to solid 645 supports at any stage of their growth scanning tunneling spectroscopy on a conducting substrate indicated an n-type metal-insulator-semiconductor (MIS) junction behavior... 

Figure 14-3. Energy diagram of a metal-insulator-semiconductor (MIS) junction at equilibrium.

In a second embodiment the imager is a metal-insulator-semiconductor, MIS, structure throughout. That is, the read lines 42, 44 and 46 and output collectors 48, 50 and 52 are MIS structures. The contiguous read lines 42, 44 and 46 and output collectors 48, 50 and 52, in another embodiment, are formed in a spaced relationship by gaps and a pulsed barrier switch is utilized to control charge flow through the gaps. The use of the pulsed barrier switch makes possible a pn-junction read line and MIS output diode, or an MIS read line and pn-junction output diode. 

Four different types of junctions can be used to separate the charge carriers in solar cebs (/) a homojunction joins semiconductor materials of the same substance, eg, the homojunction of a p—n sibcon solar ceb separates two oppositely doped layers of sibcon 2) a heterojunction is formed between two dissimbar semiconductor substances, eg, copper sulfide, Cu S, and cadmium sulfide, CdS, in Cu S—CdS solar cebs (J) a Schottky junction is formed when a metal and semiconductor material are joined and (4) in a metal—insulator—semiconductor junction (MIS), a thin insulator layer, generaby less than 0.003-p.m thick, is sandwiched between a metal and semiconductor material. 

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