UNIFORM INTERMIXING OF QUANTUM-WELLS IN P-I-N MODULATOR STRUCTURES BY IMPURITY FREE VACANCY DIFFUSION

We present the results of an investigation of impurity free vacancy diffusion (IFVD) post-growth treatments of p-i-n modulator structures. The investigation is in two parts. We first establish that gallium vacancies (V-Ga) are produced during IFVD (by measuring the intensity of the low temperature 1.2 eV signal from Si-V-Ga complexes) in a thick Si-doped GaAs sample. The second part of this work investigates the degree of intermixing of three 80 Angstrom GaAs quantum wells embedded in the intrinsic region of a p-i-n modulator at depths between 1-2 mu m from the surface. Photoluminescence studies on etched samples and cathodeluminescence showed that no significant depth dependence occurs as a result of IFVD.