Au-Ge-Ni ohmic contact for Ga-Al-As compound semiconductor

摘要

On the surface of n-type layer of Ga.sub.1-x Al.sub.x As (0≦ x. ltoreq.1) having n-type layer, Au layer is formed as a first layer, and alloying treatment is performed after Ge layer, Ni layer and Au layer are sequentially formed. The first Au layer, the second Ge layer, the third Ni layer and the fourth Au layer have the following thickness: P P______________________________________ PP 1st layer Au 10-100 Å PP2nd layer Ge 50-200 Å PP3rd layer Ni 50-200 Å PP4th layer Au 200-1000 Å;PP______________________________________ P PPPThus, it is possible to form an ohmic electrode, which has low contact resistance and does not develop ball-up phenomenon.