FABRICATION METHOD FOR INTEGRATED CIRCUIT STRUCTURES INCLUDING FIELD EFFECT TRANSISTORS OF SUB-MICROMETER GATE LENGTH, AND INTEGRATED CIRCUIT STRUCTURE FABRICATED BY THIS METHOD

摘要

For forming field effect transistors, a multilayer structure (16, 20, 21, 22, 24, 26) of different materials including a conductive layer (20) is deposited over a substrate (10). Vertical sidewalls are obtained by etching the top layers (24, 26) and a sidewall layer (30) is formed by oxidizing the sidewalls. Removing further material leaves the very fine structure of sidewall layers, which is used as a mask to etch the lower layers (22, 21, 20) so as to leave portions of the conductive layer as very fine gate electrodes, plus interconnections. Some gate electrodes of larger dimension are obtained simultaneously by covering the area between two stripes of the sidewall layer before etching down to the conductive layer.