Ohmic contacts to p-type ZnTe using electroless Pd

The characterization of electroless Pd contacts to p-ZnTe has been carried out by measuring the current-voltage curves and Auger sputter depth profiles. On the basis of the shape of the I-V characteristics, it can be concluded that electroless Pd makes a contact of much better quality than electroless Au and Pt contacts. The best contacts are achievable for Pd electrode by annealing at 200 degrees C. The specific contact resistance under this condition is estimated to be as low as 6 x 10(-4) Ohm cm(2) for p-ZnTe with a hole concentration of 3 x 10(17) cm(-3) by the method of Cox and Strack. For electroless Pd, Pd-ZnTe alloy is formed. On the other hand, electroless Au leaves oxygen contamination near the interface between ZnTe and metal, whereas electroless Pt brings out the Te intermediate layer. (C) 1999 Elsevier Science S.A. All rights reserved.