SUBSTRATE ORIENTATION EFFECTS ON DOPANT INCORPORATION IN INP GROWN BY METALORGANIC CHEMICAL VAPOR-DEPOSITION

We have investigated the doping incorporation and activation of InP growth using metalorganic chemical vapor deposition on [100], [311]B, and [110] InP substrates. Effects of orientation, growth temperature, and V/III fluxes were studied. The dopants used were Zn from dimethylzinc [(CH3)2Zn] and diethylzinc [(C2H5)2Zn], S from hydrogen sulfide [H2S], Si from silane [SiH4], and Sn from tetraethyltin [(C2H5)4Sn]. The incorporation and activation of the p-type dopant Zn are elevated on the [311]B and [110] planes, while the incorporation is suppressed for the n-type dopants (S, Si, and Sn). The n-type dopant Sn has similar incorporation and activation on the various substrate orientations studied. Anomalous Zn doping on the higher order planes [311] B and [110] lead to the Zn incorporation exceeding the solubility limit in InP. Incorporated Zn levels as high as I.0 X 10(19) CM-3 were measured, and the corresponding activated Zn level was as high as 5.4 X 10(18) CM-3 on a [110] InP substrate. Interdiffusion of the p-type dopant Zn into the S-doped n-type InP substrate is inhibited by a high S-doping level and segregates at the substrate-epilayer interface. If the S-doping level is lower than the Zn concentration, then Zn diffuses deep into the substrate at a uniform level.