Ohmic contacts to p-type InP using Be-Au metallization

A new contact to p-InP is reported with beryllium as the acceptor. The contact consists of a thin layer of 3 wt.% Be in Au alloy and a Au overlay sequentially deposited by e-gun evaporation. Alloying at 420 °C yields Ohmic contacts with low specific contact resistance rc⩽8×10−5 Ω cm2 for InP with NA−ND ≲1×1018 cm−3. To minimize the tendency of InP for thermal dissociation, the alloying temperature can be reduced to 375 °C by adding a thin Pd layer at the semiconductor metallization interface. This is achieved at the expense of a slight increase in resistance.