Characterization of p-type GaAs heavily doped with carbon grown by metalorganic molecular-beam epitaxy

Abstract

p‐type GaAs with doping levels of up to 5.8×10²⁰ cm⁻³ has been grown by metalorganic molecular‐beam epitaxy (MOMBE) using carbon (C) as a dopant. The mobility and minority‐carrier diffusion length of the C‐doped MOMBE layers were comparable to those of Be‐doped MBE layers. The diffusion coefficient of C at 900 °C was estimated to be 6×10⁻¹⁵ cm² /s which is about two orders of magnitude less than that of Be (1×10⁻¹² cm² /s). In addition, the lattice constant of C‐doped GaAs was found to be 5.6533 Å which completely matches that of the substrate, while the lattice constant of Be‐doped GaAs decreases to 5.6467 Å at a doping level of 2×10²⁰ cm⁻³ as reported by Lievin et al. [Inst. Phys. Conf. Ser. No. 7 9, 595 (1985)].