Sochin, Thickness matters. I buy Au with 12% Ge already in it. For my use, I evap 650A AuGe, then 150A of Ni, then top it off with 1700A of Au. Then I sinter it a 425c for 20 seconds. Brent sachin narwade wrote: > Dear all, > i am having a problem getting a good ohmic contact on n-GaAs. As > suggested in theory, i have used Au-Ge( 88%:12%) and evaporated them > together in a Tungsten boat in a vacuum coating unit. but i am still getting > schottky diode like characteristics of the contact. i have also annealed the > sample after metallization at temperatures like 360-400 degrees C (not RTA) > for 1-2 mins but still am not getting good ohmic contact. is there any > specific thing i should follow while evaporation? kindly suggest me any > solutions.