the deeper diffusion front increased when the supply of vacancies was suppressed.

The Cd was diffused into InGaAs by using Cd3P2 plus P or Cd3P2 plus Cd3As2 as diffusion sources. Two diffusion fronts were observed. The diffusion characteristics of Cd3P2 plus P sources were explained in terms of the interstitial-substitutional model or the vacancy complex model. The charge state of the diffusing interstitial Cd atom was a singly ionized donor. Gaseous Cd originated from solid-phase CdP2. In the case of Cd3P2 plus Cd3As2 diffusion sources, the effective diffusion coefficient and the surface acceptor concentration decreased with increasing weight fraction of Cd3As2. The relative depth of K.I.Ohtsuka, T.Matsui, H.Ogata: Japanese Journal of Applied Physics, 1988, 27[2], 253-9