Chemical beam epitaxial growth of Si-doped GaAs and InP by using silicon tetraiodide

Silicon tetraiodide (SiI4), which has a very weak Si-I bond strength (70 kcal/mol), is successfully employed as a novel Si dopant in the chemical beam epitaxy of GaAs and InP. No precracking is necessary before supplying SiI4 with He carrier gas. High electrical quality is ascertained for both GaAs and InP with linear Si doping controllability in the range from 2x10(16) to 6x10(18) Cm-3 With a uniformity of less than 2% within a 3-in.-diam area. The electron mobility in a GaAs with a carrier concentration of 1x10(17) cm(-3) is 4400 cm(2)/V s and that in InP with a carrier concentration of 4x10(17) cm(-3) is 2400 cm2/V s, respectively. Abrupt interfaces and precise on-off controllability without any memory effect is also confirmed by secondary-ion-mass, spectroscopy measurements. The electrical activation ratio of Si in SiI, for both GaAs and InP is almost 100% in the range studied here. These versatile features suggest that SiI4 is a promising candidate as a Si dopant source for chemical beam epitaxy growth. (C) 1996 American Institute of Physics.