LOW-TEMPERATURE GROWTH OF GAAS AND ALAS BY DIRECT REACTION BETWEEN GACL3, ALCL3 AND ASH3

Low temperature growth of GaAs and AlAs was studied by direct reaction between CaCl3, AlCl3 and undecomposed AsH3, using a hybrid furnace equipped with both infrared lamp heating and resistive heating. When solid arsenic (As4) was used as the arsenic source, the growth of GaAs and AlAs was obtained at substrate temperatures of 500-650-degrees-C and above 650-degrees-C, respectively. On the other hand, a much lower temperature (approximately 300-degrees-C) growth of GaAs could be obtained when undecomposed AsH3 was used. The growth of AlAs, however, was obtained at only above 500-degrees-C, even for the direct reaction between AlCl3 and undecomposed AsH3. This is due to the fact that a higher temperature is necessary to reduce the AlCl3 compared with GaCl3. The difference of the growth temperatures between GaAs and AlAs, and between growth with As4 vapor and with undecomposed AsH3, could be qualitatively explained by the thermodynamic analysis.