SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING SAME

摘要

The semiconductor device has a semiconductor body (1) having a field effect transistor (4) at a first surface (2) and a second gate (10) at a second surface (3). The second gate is present in a recess (11) in the semiconductor body (1) which is accurately aligned with a first gate (8) of the field effect transistor (4) on the first surface (2). The method of manufacturing the semiconductor device comprises the step of implanting ions into a semiconductor body (1) which has a first gate (8) on a first surface (2) and a silicon oxide layer (17) on a second surface (3). The implantation is done from the first surface (2) in a direction substantially perpendicular to that surface. The implantation has the effect that behind the first gate (8) an implanted region (18) is formed in the semiconductor body (1) and a circumferential implanted zone (19) in the silicon oxide layer (17). Silicon oxide is formed in the implanted region (18) by dopant-enhanced oxidation. The silicon oxide layer (17) and the silicon oxide in the region (18) are removed so as to form a recess (11), which is filled with second gate material (20) from which the second gate (10) is formed. The second gate is effective in suppressing short-channel effects.