Process for manufacturing buried channels and cavities in semiconductor wafers

摘要

The process comprises the steps of forming, on a monocrystalline-silicon body (11), an etching-aid region (13) of polycrystalline silicon; forming, on the etching-aid region (13), a nucleus region (17) of polycrystalline silicon, surrounded by a protective structure (26) having an opening (22') extending as far as the etching-aid region (13); TMAH-etching the etching-aid region (13) and the monocrystalline body (11), forming a tub shaped cavity (30); removing the top layer (19) of the protective structure (26); and growing an epitaxial layer (33) on the monocrystalline body (11) and the nucleus region (17). The epitaxial layer, of monocrystalline type (33a) on the monocrystalline body (11) and of polycrystalline type (33b) on the nucleus region (17), closes upwardly the etching opening (22'), and the cavity (30) is thus completely embedded in the resulting wafer (34).