Afield transistor with a structure similar has na = 2x10^17cm-3 , qf/q =2x10^11 cm-2 and an n+ poly-si local interconnect as the gate electrode. if the requirement for sufficient isolation between the field device and well is vt ≥ 20v, calculate the minimum field oxide thickness. assume that fermi level of n+ polysilicon coincides with ec.

(b) a mosfet has a threshold voltage of vt = 0.6v, a subthreshold swing of 90 mv/decade and a drain current of 0.1μa at vt. what is the sub-threshold leakage current at vg = 0v?

(c) for the device in problem 5(b), calculate the reverse substrate voltage required in order to decrease the sub-threshold leakage current by one order of magnitude or one decade. na=3x10^17cm-3 , d= 6 nm. hint: every one decade decrease of sub-vt leakage current => 90 mv increase in vt => δvt=90 mv or 0.09v [for problem 5(b)].