Chapter 7: MOS Field-Effect-Transistors

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Examples

Example 7.1  print file in PDF format

Calculate the drain current of a silicon nMOSFET with VT = 1 V, W = 10 mm, L = 1 mm and tox = 20 nm. The device is biased with VGS = 3 V and VDS = 5 V. Use the quadratic model, a surface mobility of 300 cm2/V-s and set VBS = 0 V.

Also calculate the transconductance at VGS = 3 V and VDS = 5 V and compare it to the output conductance at VGS = 3 V and VDS = 0 V.

Example 7.2  print file in PDF format

Repeat example 7.1 using the variable depletion layer model. Use VFB = -0.807 V and Na = 1017 cm-3.

Example 7.3  print file in PDF format

Calculate the threshold voltage of a silicon nMOSFET when applying a substrate voltage, VBS = 0, -2.5, -5, -7.5 and -10 V. The capacitor has a substrate doping Na = 1017 cm-3, a 20 nm thick oxide (eox = 3.9 e0) and an aluminum gate (FM = 4.1 V). Assume there is no fixed charge in the oxide or at the oxide-silicon interface.