PCS 224 Lecture 28: nov 17 flatband
27 Nov 2015
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Same number of holes as acceptor ions therefore it is flat. Qsd = 0 (the white region on the bottom right triangle of the q"m and q"ss diagram. Q"ss = 10^11*e = c/cm^2 = 1. 6 e-8. Cox = e ox / tox = eox / 0. 1micrometer = 3. 45e-13 f/cm / 1e-4microcentimeter = Eox = 3. 9 e0, where e0 = 8. 85e-12 f/m 8. 85e-14 f/cm eox = 3. 45e-13. Which of the following is not true for flat band there is no free charge near the semiconductor surface in the substrate. Accumulation negative effect gate bias , hole accumulate under the gate is more important than electrons being expelled under the gate region under the gate. For a p substrate mosfet, what is wrong for accumulation mode vgs must be positive this is wrong. Vt = 1 and vfb = 2, it is pmos. Vfb vt for n mos (accumulation inversion negative here, electrons is majority)
