Zn doping of InP, InAsP/InP, and InAsP/InGaAs heterostructures through metalorganic vapor phase diffusion (MOVPD)

Zinc incorporation by post-growth metalorganic vapor phase diffusion (MOVPD ) is used to achieve high p-doping, which is desirable for the fabrication of photodiodes. Diethylzinc (DEZ) is used as precursor and Zn is diffused i nto InP and InAs0.6P epitaxial layers grown by low pressure metalorganic va por phase epitaxy (MOVPE) on different substrate orientations, enabling the investigation of the dislocation density on the Zn incorporation. Diffusio n depths are measured using cleave-and-stain techniques, resistivity measur ements, electrochemical profiling, and secondary ion mass spectroscopy. Hig h hole concentrations of, respectively, 1.7 X 10(19) and 6 X 10(18) cm(-3), are obtained for, respectively, InAs0.60P and InP. The diffusion coefficie nts are derived and the Zn diffusion is used for the fabrication of lattice -mismatched planar PIN InAsP/InGaAs photodiodes.