Patent ID: 7700417

Claim:
A method for forming a cascode current mirror using MOS transistors, comprising: providing a semiconductor substrate of a first conductivity type; forming a first dielectric layer on a first portion of the semiconductor substrate; forming a second dielectric layer on a second, different, portion of the semiconductor substrate and thinner than the first dielectric layer; forming a conductor over the first and second dielectric layers; forming from the conductor, first and third spaced apart gates on the second dielectric layer over the second portion of the semiconductor substrate and second and fourth spaced apart gates on the first dielectric layer over the first portion of the semiconductor substrate; doping multiple spaced apart regions of the substrate with a dopant of a second, opposite conductivity type, thereby forming source and drain regions in the substrate, wherein a first source regions is adjacent a first lateral side of the first gate, a second source region is adjacent a second lateral side of the second gate, a third source region is adjacent a third lateral side of the third gate, a fourth source region is adjacent a fourth lateral side of the fourth gate, and a first drain regions is adjacent a fifth lateral side of the first gate, a second drain region is adjacent a sixth lateral side of the second gate, a third drain region is adjacent a seventh lateral side of the third gate, a fourth drain region is adjacent an eighth lateral side of the fourth gate and the first drain region is coupled to the second source region and the third drain region is coupled to the fourth source region; and electrically coupling the first and third gates to each other and to the first drain region and electrically coupling the second and fourth gates to each other and to the second drain region.