Method of etching a layer of polycrystalline si1 - xgex or of a stack of a layer of polycrystalline si1 - xgex and a layer of polycrystalline si, and its application to the microelectronics

摘要

A process for etching of a polycrystalline Si1-xGex layer (0x = 1) on a substrate or of a stack comprising a silicon layer deposited on a polycrystalline Si1-xGex layer on a substrate involves anisotropic etching of the polycrystalline Si1-xGex layer or the stack, using an inorganic material mask provided on the layer or stack, by means of a high density plasma of a gaseous mixture of Cl2 + N2, Cl2 + NH3 or N2 + NH3. Preferably, this etching step is terminated before reaching the substrate and may be followed by over-etching with a high density plasma of a gaseous Cl2 + N2 or Cl2 + NH3 mixture.