The growth of a GaP epilayer on Si substrates by metallorganic CVD

Abstract

Single crystal GaP epilayers can be grown successfully by metallorganic vapour phase epitaxy on Si substrates by thermal decomposition of a gas mixture of triethylgallium (TEG) and phosphine (PH₃). The optimum growth temperature and the optimum mole ratio of P and Ga were 660 degrees C and 13 to 1, respectively. The as-grown GaP layer was n-type. The concentration and mobility of GaP layers at room temperature were in the range 3*10¹⁶-8.5*10¹⁶ cm^-3 and 50-100 cm² V^-1 s^-1, respectively. I-V and C-V characteristics of this heterojunction device were measured. The leakage current was a few tenths of a mu A and the breakdown voltage was 12 V. A linear relationship of C^-2.08 and voltage can be obtained. There is a wide wavelength range of photo-response (from 0.5 mu m to 1.2 mu m) for this diode. The dependence of open-circuit voltage and short-circuit current on light intensity were also measured.