Hi,

I am currently working with AlGaAS/AlAS/GaAs material.

I was trying to measure relative permissivity of AlAs layer and I made a
capacitor using AlGaAs layer as top and bottom electrode. But I could not
measure the capacitance and I think the oxide on top of AlGaAs blocked my
probe tip to get ohmic contact. I tried to dip the sample into diluted HCl
and found the capacitance is changing much.

Does anyone tried to get ohmic contact to AlGaAs layer using probe tip?

Any information regarding this is appreciated.

Thanks for your attention!

Lihua Li
Department of Mechanical Engineering
Univ. of Maryland
TEL: 301-405-2981