Diffusion of Cd and Zn into InP and InGaAsP (E_g=0.95-1.35 eV)

Abstract

The diffusion of Cd and Zn into InP was investigated at temperatures ranging from 566°C to 715°C. Cd diffusion using a combination source composed of Cd 3 P 2 and InP powder allows us to establish a shallow diffusion depth (X j ) of less than a few microns and to form a highly planar p-n junction without surface deterioration. On the other hand, Zn diffusion using a combination source consisting of Zn 3 P 2 (or ZnP 2 )+InP powder proceeded rapidly and resulted in irregular diffusion fronts. When selective diffusion of Cd into InP was carried out using a PSG film mask, slip dislocations were found to be generated along the mask edge if the amount of InP powder in the diffusion ampoule was not sufficient (≤100 mg). Cd diffusion into InGaAsP ( E g =0.95–1.35 eV) lattice matched to InP was also carried out, and it was found that the diffusion depth decreases monotonically with decreasing band gap energy.