TY - JOUR
T1 - A surface ir study of inorganic film formation GaAs, silicon and germanium by aqueous NH4F, and HF
AU - Burrows, V. A.
AU - Yota, J.
N1 - Funding Information:
The authors would like to thank Y. J. Chabal and S. B. Christman of AT&T Bell laboratories for important technical advice. They also thank J. M. Fountain and C. T. Lenczycki for experimental assistance and useful discussions. This work has been supported by the National Science Foundation (Grant DMR 87-008153).
PY - 1990
Y1 - 1990
N2 - Hydrofluoric acid buffered with ammonium fluoride (BHF) is a common cleaning-stripping solution used in silicon processing. Little is known of the surface chemistry which occurs as a result of BHF treatment. Surface IR spectroscopy in the multiple internal reflection mode was used to study silicon, germanium, and gallium arsenide surfaces treated with BHF. For each of these materials, the BHF not only dissolved the native oxide, but also deposited a film comprising ammonium salts (NH4F and NH4F·HF). These salts subsequently slowly reacted with the semi-conductor substrate to form hexafluorometallate compounds ((NH4)2SiF6, (NH4),GeF6, and (NH4)3GaF6). Although the original ammonium fluoride and bifluoride salts are quite soluble in alcohols as well as aqueous solutions, the hexafluorometallates are completely insoluble in alcohols, and can only be removed by careful water or aqueous acid rinse. The presence of these previously unsuspected films could seriously degrade electronic performance of the materials.
AB - Hydrofluoric acid buffered with ammonium fluoride (BHF) is a common cleaning-stripping solution used in silicon processing. Little is known of the surface chemistry which occurs as a result of BHF treatment. Surface IR spectroscopy in the multiple internal reflection mode was used to study silicon, germanium, and gallium arsenide surfaces treated with BHF. For each of these materials, the BHF not only dissolved the native oxide, but also deposited a film comprising ammonium salts (NH4F and NH4F·HF). These salts subsequently slowly reacted with the semi-conductor substrate to form hexafluorometallate compounds ((NH4)2SiF6, (NH4),GeF6, and (NH4)3GaF6). Although the original ammonium fluoride and bifluoride salts are quite soluble in alcohols as well as aqueous solutions, the hexafluorometallates are completely insoluble in alcohols, and can only be removed by careful water or aqueous acid rinse. The presence of these previously unsuspected films could seriously degrade electronic performance of the materials.
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U2 - 10.1016/S0040-6090(05)80047-1
DO - 10.1016/S0040-6090(05)80047-1
M3 - Article
AN - SCOPUS:0025592637
SN - 0040-6090
VL - 193-194
SP - 371
EP - 381
JO - Thin Solid Films
JF - Thin Solid Films
IS - PART 1
ER -