WEEK 3 TASK 8, find the oxide charge density at the flatband condition and at the midgap condition

First of all, the relationship between gate voltage and surface potential is defined below:

The figure (1) is an example of "Effects of bulk oxide charge for an n-type MOS-C", it is very similar to the p-type condition. 

(1)

The figure (2) is the comparison ideal and real midgap of p-type condition, 

(2)

Essentially, there have two conditions need to be concerned. 

Flatband condition:

the idear VG is 0 V, and the real Vg has been calculated in the task 6 which is 0.265 V, so that the delta V is -0.265 V.

=-1.57527* 10^16  (m^-2) =-1.57527*10^12 (cm^-2)

Midgap condition:
=0.3172 eV

the ideal VG is

=0.3316V
so that deltV is -0.4864

=-2.8913*10^16  (m^-2)  = -2.8913*10^12 (cm^-2)