Question

a) After you fabricated your ED-NMOS chip, you measured the threshold voltage of NMOS transistor and found that you missed the target threshold voltage. The actual threshold voltage was +0.4V while the target value was +0.8V. What should VBB be set at in order to set the threshold voltage of the driver (grounded source) transistors at VT = +0.8V? Assume that this VBB is applied throughout the rest of this problem unless otherwise specified.

b) Calculate the arsenic implant dose required to set the depletion threshold of the load devices at -3V with VBB applied as in part above. Assume this is the depletion threshold (for a grounded source). What is this load device threshold when the source pulls up to +5V?

Answer 1