Method of forming semimicron grooves in semiconductor material

Abstract

On a layer having a stepped relief, such as a masking layer (4) having openings (5) on a substrate region, (2) a first layer (6) is provided, which, while maintaining the stepped relief, is covered by a second masking layer (8) and a convertible layer (9). By conversion of the convertible layer (9) (by means of ion implantation, oxidation, silicidation) this layer becomes selectively etchable. After removal of the non-converted parts, an intermediate mask (8) is formed with an opening in the second masking layer (8) along the edge of a depression (7). By means of the mask (8) thus obtained, grooves (11) are formed by anisotropic etching in the first layer (6) and in the subjacent substrate region (2) if required. When grooves are formed in a substrate region (2) of semiconductor material, these grooves may be filled with oxide (25) for forming insulated regions. If a first layer (6) of polycrystalline silicon is used on a substrate region (2) of silicon, this layer (6) can serve as a doping source and a connection, respectively. Thus, various kinds of transistors (MOSFET and bipolar transistors) can be manufactured. The second masking layer (8) and the convertible layer (9) may be realized, if required, as a single layer (65).