Autocatalytic Deposition of Gold and Palladium onto n ‐ GaAs in Acidic Media

Deposition of gold, palladium, and gold‐palladium alloys is obtained with the help of acidic electroless baths of low metal content. The baths are prepared by suitably mixing separate solutions containing the reductant (hydroxylamine hydrochloride) or one of the desired cations respectively, with suitable additives. The stability of the baths with time is good and their replenishment easy to realize. Provided that a suitable choice of mixture of the three solutions is made, they allow the fabrication of multilayered heterostructures which could be fruitfully used for ohmic contact preparation onto without any initial activation step. The deposition mechanism of gold and palladium and the effect of adding palladium to gold is discussed.