Patent ID: 7547639
Filing Date: 2009-06-16
Classification: H01L,Y02E

Abstract:
1. A method, comprising: forming a germanium layer on a semiconductor substrate; forming a nitride layer on the germanium layer; forming an oxide on the nitride layer; forming a photoresist layer on the oxide layer; patterning the photoresist layer to have an opening; performing a first etch to the oxide layer through the opening with a first chemistry; performing a second etch to the nitride layer through the opening with a second chemistry, the second etch being a timed dry etch that etches through about 75% to about 90% of the nitride layer with a second chemistry, to produce a protective nitride buffer over the germanium layer, the protective nitride buffer being about 10% to about 25% of an original thickness of the nitride layer; removing the photoresist layer with a third chemistry to which the germanium layer is sensitive, the protective nitride buffer protecting the underlying germanium layer from the third chemistry; performing a third etch to the protective nitride buffer, the third etch being a timed etch that etches through the approximate 10% to 25% of the nitride layer that was not previously etched in the second etch; and wet cleaning a surface of the germanium layer with a fourth chemistry that cleans the surface and conditions the atomic termini of the surface to be primarily either hydrophobic or hydrophilic.