Method of forming a self-aligned contact utilizing a polysilicon layer

Abstract

A method of forming a contact region having an insulating layer which is etch protected, which includes sequentially depositing a gate oxide layer 2, a first conducting layer 3 for gate electrode, a first insulating layer 4 and a second conducting layer 5 on a silicon substrate 1. A portion of the second conducting layer 5 is etched to form an etch protective layer 5A. Portions of the etch protective layer 5A, the first insulating layer 4 and the first conducting layer 3 are sequentially etched to form separated gate electrodes 3a and 3b and separated etch protective layers 5a and 5b on the gate electrodes 3a and 3b, respectively and to expose a portion of the gate oxide layer 2 to define a source region 1A. A second insulating layer 6 is deposited on the entire surface of the resulting structure. The second insulating layer 6 is etched to form a spacer 6a on each of the side walls of the gate electrodes 3a and 3b and on the first insulating layer 4 and to expose the source region 1A. A third insulating layer 7 is deposited on the entire surface of the resulting structure. A contact region 10 is formed by selectively removing the third insulating layer 7 and the gate oxide layer 2 on the source region 1A and portions of the third insulating layer 7 on the etch protective layers 5a and 5b to form a contact region having an etch protected insulating layer.