In situ contacts to GaAs based on InAs

We report preliminary electrical results on n+-InAs/n-GaAs contact structures grown by molecular beam epitaxy. The data indicate that the conduction-band discontinuity is sufficiently small to allow the formation of an ohmic contact to n-type GaAs for very heavily doped InAs layers. The structures require a short-term anneal to obtain a low resistance contact. An InAs layer which is only 200 Å thick is sufficient to provide a specific contact resistance of 10-6 Ω cm2. The contacts appear to be thermally stable for short-term anneals up to 900°C.