Question

A technique used to reduce the magnitude of threshold voltage of MOSFET?

(a) Use of complementary MOSFET

(b) Use of Silicon nitride

(c) Using thin film technology

(d) None of the mentioned

The question was posed to me during an interview for a job.

I'd like to ask this question from Fabrication of FET topic in division IC Fabrication of Linear Integrated Circuits

Answer 1

The accurate choice is (b) Use of Silicon nitride

Unravel the mysteries with: Silicon nitride is sandwiched between two SiO2 layer and provide necessary barrier .The dielectric constant of Si3N4 is 7.5, whereas that of SiO2 is 4. This increase in overall dielectric constant reduces threshold voltage.