Undoped superlattice structures were grown, with or without the presence of 120Sn implants, by using molecular beam epitaxy. They were then annealed under Si3N4, SiO2 or encapsulant films. It was found that an enhancement of the Al-Ga interdiffusion coefficient occurred under the Si3N4 and SiO2 films, due to the in-diffusion of Si from the films. The enhancement was greater during diffusion of the Sn implant. In both cases, intermixing enhancement was attributed to the operation of the Fermi effect. Beneath the WNx film, interdiffusion was suppressed even in the presence of the Sn dopant.

E.L.Allen, C.J.Pass, M.D.Deal, J.D.Plummer, V.F.K.Chia: Applied Physics Letters, 1991, 59[25], 3252-4