Polysilicon Deposition Process
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
This article relates generally to integrated circuit fabrication and, more particularly, to deposition of multiple layers of polysilicon. The application of an oxide layer to a polysilicon gate by chemical vapor deposition followed by reactive ion etching enables better profile control and support of the second polysilicon layer. In Fig. 1, gate oxide formation 1 on silicon substrate 2 includes deposition of polysilicon layer 3 covered by oxide layer 4 that is deposited by chemical vapor deposition. This stack is photolithographically defined and anisotropically etched to form the gate. Another oxide layer 5 is then deposited by chemical vapor deposition in Fig. 2. Reactive ion etching removes the deposited oxide 5, but forms sidewalls 6, as in Fig. 3.