Tin doping in Ga0.47In0.53As and Al0.48In0.52As grown by molecular-beam epitaxy

Abstract

Transport properties of Sn‐doped Ga_0.47In_0.53As and Al_0.48In_0.52As epitaxial layers grown lattice matched to InP substrates by molecular‐beam epitaxy (MBE) have been studied. Doping levels as high as 2×10¹⁹ cm⁻³ have been achieved for both n‐types Ga_0.47In_0.53As and Al_0.48In_0.52As. The carrier concentration varies proportionally with the arrival rate of Sn and the sticking coefficient of Sn in these ternary systems is estimated to be unity. For the same Sn arrival rate, the carrier concentrations in both ternary epitaxial layers are identical. Mobility studies showed that the results with MBE grown Sn‐doped Ga_0.47In_0.53As layers are comparable to the best reported with liquid phase epitaxy (LPE). The variations of electron mobility as a function of carrier concentration are in excellent agreement with the results of the theoretical calculations involving the alloy scattering mechanism at both room and liquid‐nitrogen temperatures. The electron mobility variation in Al_0.48In_0.52As epitaxial layers follows the same trend as that in Ga_0.47In_0.53As epilayers. For the same carrier concentration, however, the value is only 1/6 of that of the Ga_0.47In_0.53As.