Verfahren zur Herstellung eines Kontaktlochs zu einem dotierten Bereich

摘要

A doped region (2a) is made in a substrate (10) such that it is bounded by insulation regions (12, 13) at least at the surface of the substrate (10). An undoped silicon layer (4) is deposited over the entire surface. A doped zone (4c) which reliably overlaps the region for the contact hole is selectively produced in the silicon layer (4). Undoped parts of the silicon layer (4) are removed selectively with respect to the doped zones (4c). An insulation layer (6) is produced over the entire surface, in which insulation layer a contact hole (7a) is opened by anisotropic etching of the silicon layer (4) selectively with respect to the doped zone (4c). The method is suitable for making compact bit line contacts in DRAMs with p-channel MOSFETs in the cell field and can particularly advantageously be combined with the so-called BOSS process (boron outdiffused silicon strap).