SCHOTTKY AND OHMIC CONTACTS OF PD ON P-TYPE GAAS DISTINGUISHED WITH HYDROGEN

Contacts of Pd on p-type GaAs with a native oxide layer between them r eveal ohmiclike behavior in air or vacuum at room temperature. This be havior is similar to that of contacts annealed at 450-degrees-C for 5 min. To relate the interface electrical properties of the two contacts to their interfacial structures, we propose to measure current-voltag e (I-V) and capacitance-voltage (C-V) characteristics in a hydrogen am bient. We show that these two contacts can be distinguished with atomi c hydrogen. This method was confirmed with I-V and C-V measurements at low temperatures.