The behavior of an MOS capacitor is defined by its bias states: Accumulation Negative voltage is applied to a p-type substrate. Majority carriers (holes) gather at the surface. The device acts like a simple parallel-plate capacitor. A small positive voltage is applied. Holes are pushed away from the interface. A region of fixed negative ions (depletion layer) forms. Voltage exceeds the . Electrons are pulled to the surface. A thin n-type layer (the inversion layer) is created. 💡 This allows current to flow between Source and Drain. 3. Key Performance Parameters To optimize MOS devices, engineers focus on:
Traditionally made of aluminum, though modern chips use "High-k Metal Gates" (HKMG) often made of polycrystalline silicon or specific metal alloys. Oxide (Insulator): Usually Silicon Dioxide ( SiO2cap S i cap O sub 2 mos -metal oxide semiconductor- physics and technology pdf