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Title: Method using laser irradiation for the production of atomically clean crystalline silicon and germanium surfaces

Patent ·
OSTI ID:5068798

This invention relates to a new method for removing surface impurities from crystalline silicon or germanium articles, such as off-the-shelf p- or n-type wafers to be doped for use as junction devices. The principal contaminants on such wafers are oxygen and carbon. The new method comprises laser-irradiating the contaminated surface in a non-reactive atmosphere, using one or more of Q-switched laser pulses whose parameters are selected to effect melting of the surface without substantial vaporization thereof. In a typical application, a plurality of pulses is used to convert a surface region of an off-the-shelf silicon wafer to an atomically clean region. This can be accomplished in a system at a pressure below 10-/sup 8/ Torr, using Q-switched ruber-laser pulses having an energy density in the range of from about 60 to 190 MW/cm/sup 2/.

DOE Contract Number:
W-7405-ENG-26
Assignee:
TIC; ERA-05-035145; EDB-80-106852
OSTI ID:
5068798
Country of Publication:
United States
Language:
English