Metal-oxide-semiconductor capacitor using genetic semiconductor compound as dielectric

摘要

1,129,272. MOS capacitors. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 3 Jan., 1966 [5 Jan., 1965], No. 67/66. Heading H1M. In manufacturing a metal-oxide-semi-conductor capacitor, a silicon wafer 1 of high resistivity, e.g. about 0À5 ohm-cm., has a surface portion 4 rendered semi-conducting by diffusion into it of boron or phosphorus dopant, the concentration of dopant at the surface of portion 4 is reduced by thermal oxidation to form a silicon oxide layer which acts as a "getter" and is removed by acid etching, silicon oxide layer 8 is now formed by thermal oxidation of the relatively pure surface of layer 4, aluminium contact 11 is vacuum deposited on to layer 4 through a window etched in the oxide layer and counter electrode 10 deposited at the same time on the oxide layer except for an area around contact 11. Surface dopant on layer 4 may alternatively be removed by heating under vacuum. The capacitor may be readily incorporated in an integrated circuit, since connections to both electrodes are on the same side.