Properties of GaAs on Si grown by molecular beam epitaxy

Abstract For several years, there has been a great deal of activity in the growth of GaAs and other compounds on Si substrates for several reasons. Among them are the high quality, low cost, high thermal conductivity, and mechanical strength offered by Si substrates. For example, if we compare the cost of GaAs and Si wafers, the Si substrate can be regarded as free. Presently, 3 in. is the maximum GaAs wafer diameter in comparison to the current 8-in. and expected 10-in. Si wafer sizes. The growth of GaAs on such Si wafers is an advantageous way of growing GaAs on large-diameter wafers. But the second, and most exciting motivation for GaAs on Si, is the hybridization of Si and GaAs technologies on the same wafer. GaAs and Si technology are highly complementary and compatible. The advantage of Si over GaAs is its highly developed processing technology and the very high integration density of circuits available. The advantage of GaAs over Si is its intrinsically higher performance potential and its optical properties. Therefore, the value of hybridization of GaAs and Si technologies is apparent. For example, this system is well suited for optical off-chip communication and one can imagine a single chip where the high speed devices and optical inputs and outputs are driven by GaAs devices and the highly integrated part of the circuits are in Si technology.