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Unformatted text preview: eposition of the oxide). These are called surface state charges (per unit area), denoted by Qss’. It turns out that on a (100) surface, the surface state charges are one order of magnitude smaller than those on a (111) surface. Therefore, the industry standard is to use (100) surfaces. Now that we have two non ideal factors: work function difference and surface state charges, we need to find the flat band voltage first. From the flat band condition, we can then talk about accumulation, depletion, and inversion, as in the case of an ideal MOS capacitor. Consider only metal semiconductor work function difference φms first. To reduce the depletion region toward flat band, the gate bias needs to be negative. When VFB = φms, which...
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 Winter '08
 WANG
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