Epitaxially grown compound semiconductor crystals with buffer layers.

摘要

on a substrate, e.g. a GaS or InP crystal wafer (21), are grown epitaxially and successively, e.g. in vapor deposition apparatus of Fig. 1, an optional undoped InAs or InP layer (20) 10 ANGSTROM to 1 mu thick, a buffer layer comprising: (A) a high-resistivity layer ( 19 ) of thickness 2, 000 ANGSTROM to 5 mu m of AlGaAs preferably of composition Al(0.1-0.8) Ga(0.9-0.2) As or AlGaInP which is doped with oxygen and/or transition metal in total amount of 1 x 10<1><7> to 1 x 10<2><0> atoms/cm<3>, and (B) a layer (18) of thickness 1, 000 to 20, 000 ANGSTROM of GaAs, InGaP or AlGas of high purity such that the total concentration of donor impurities, acceptor impurities and active defects is 1 x 10 <1><6> per cm<3> or less, and an active layer (17), e. g. of n-type GaAs or InGaP. Sources for the crystals can be vaporized trialkyl gallium or indium, arsine, hydrides of As and P; and as oxygen dopants O2 gas diluted with H2 or an inert gas or an aluminum or transition metal alkoxide provided the dopant has little residual effect. The layered compound semiconductor crystals provided are useful as high-speed electronic elements, especially in making a field-effect transistor (see Figs. 3 and 4) with little hysterisis or kink. <IMAGE>