PRESERVATION OF INDIUM-PHOSPHIDE SUBSTRATES - THE IN-SN-P MELT REVISITED

Using Auger electron spectroscopy and secondary ion mass spectrometry, we have detected very high levels of tin (approximately 10**2**1/cm**3) on (100) InP substrates preserved at high temperatures (650 degree -700 degree C) with phosphorus vapor supplied by an In-Sn-P solution. Depth profiling through InP epilayers grown on preserved substrates, however, indicates no tin buildup at the epilayer/substrate interface. Surface studies and depth profiling of control samples reveal that the tin accumulated during preservation is restricted to the near-surface region (approximately less than 10 Angstrom) and readily dissolves into an In-P melt.