Improved process for preparing cleaned surfaces of strained silicon
AssigneeS.O.I.Tec Silicon on Insulator Technologies
InventorsKhalid Radouane, Alessandro Baldaro
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Abstract
The present invention relates to a method of treating wafers comprising at least one surface layer of silicon-germanium (SiGe) and a layer of strained silicon (sSi) in contact with the SiGe layer, the sSi layer being exposed by etching of the SiGe layer, the method comprising the steps of: (a) a first selective etch of the SiGe layer, optionally followed by an oxidative cleaning step; (b) a rinsing step using deionized water; (c) drying; and (d) a second selective etch step. The present invention relates to a wafer comprising at least one surface layer of strained silicon (sSi), said surface layer of sSi having a thickness of at least 5 nanometres and at most 100 μm of at most 200 defects per wafer.
Claims20
A method of treating at least one wafer comprising at least one silicon-germanium (SiGe) layer and a strained silicon (sSi) layer in contact with the at least one SiGe layer, the sSi layer being exposed by etching of the at least one SiGe layer, the method comprising the steps of:
- (a) selectively etching the at least one SiGe layer in a first selective etch process;
- (b) rinsing at least a portion of the at least one wafer using deionized water;
- (c) drying the at least a portion of the at least one wafer;
- and
- (d) selectively etching any remaining SiGe of the at least one SiGe layer in a second selective etch process.
A wafer comprising at least one surface layer of strained silicon (sSi), the surface layer of sSi having a thickness of at least 5 nanometres and at most 100 nanometres, and a sum of defects (SOD) value SOD @ 0.40 μm of at most 200 defects per wafer.
Dependencies are inferred from the claim text.