Self-Aligned Polysilicon Gate MOSFETS with Tailored Source and Drain Profiles
Original Publication Date: 1980-Apr-01
Included in the Prior Art Database: 2005-Feb-13
The Sharp impurity profile of the drain junction of an ion-implanted MOSFET tends to have a lower junction breakdown voltage and a higher probability of hot electron injection into the gate oxide than a graded drain junction. This article describes a method to form the source and drain regions using two or more doping steps with ion implantations or thermal diffusion processes. The junction profile is tailored by using independently self-aligned doping processes which can be controlled with a high degree of accuracy.