Integrated circuit MOSFET current mirror amplifier - has two transistors with drain extensions of lower impurity concn. than drains and sited in drain-source channel

摘要

The current mirror amplifier has a graded diffusion impurity concentration in its first semiconductor zone (15, 58) in which two MOSFETs are formed with a max. concentration at the surface. N-type drain extensions (56, 54) meet the drain zones (D, 55, 53) of the MOSFETs and have lower impurity concentrations than the drain zones. The drain extensions are located in the drain/source channels of the two MOSFETs. They extend sufficiently far into the first semiconductor zone to eliminate the effect of channel shortening and to make the current gain independent of unequal input and output voltages.