The ultraviolet absorpton spectra of selected organometallic compounds used in the chemical vapor deposition of gallium arsenide

Abstract

Ultraviolet absorption spectra and absolute absorption cross sections of trimethylgallium (CH 3) 3Ga, triethylgallium (C 2H 5) 3Ga, trimethylarsine (CH 3) 3As, and triethylarsine (C 2H 5) 3As have been recorded as a function of temperature. Room temperature peak absorption cross sections of 2.6×10 -17, ~1.7×10 -17, 5.6×10 -17, and 4.1×10 -17 cm 2, respectively, were obtained for the above compounds at 195.0, ~190.0, 201.0, and 208.5 nm. (CH 3) 3As and (C 2H 5) 3As were found to be thermally stable up to 350° C, whereas (CH 3) 3Ga and (C 2H 5) 3Ga began to show decomposition at approximately 300–350° C. This study resolves previous discrepancies in the absorption cross section for (CH 3) 3Ga, and provides data for photo-enhanced deposition studies and optical diagnostic measurements in conventional chemical vapor deposition.