Method of making a polysilicon carbon source/drain heterojunction

Abstract

The present invention includes forming a conductive layer on a substrate. Portions of the conductive layer are removed using a first photoresist layer as a mask. A first oxide layer is formed over the conductive layer and the substrate, and an amorphous silicon layer is then formed on the first oxide layer. After annealing the amorphous silicon layer, thereby transforming amorphous silicon layer to a polysilicon layer, a second oxide layer is formed on the polysilicon layer. The second oxide layer is removed using a second photoresist layer as a mask. An amorphous silicon carbon layer is formed over the second oxide layer and the polysilicon layer, and a heavily-doped amorphous silicon carbon layer is formed on the amorphous silicon carbon layer. After annealing the heavily-doped amorphous silicon carbon layer and the amorphous silicon carbon layer, thereby transforming the heavily-doped amorphous silicon carbon layer to a heavily-doped polysilicon carbon layer, and transforming the amorphous silicon carbon layer to a polysilicon carbon layer, portions of the polysilicon carbon layer, the heavily-doped polysilicon carbon layer and the polysilicon layer are removed using a third photoresist layer as a mask.