HgTe contacts to p‐HgCdTe

HgTe contacts were fabricated on p‐HgCdTe and compared to electroless Au contacts. Both metals resulted in contacts to multiwire infrared HgCdTe which were nonohmic as deposited, but became ohmic with a specific contact resistance below 0.1 Ω cm² after a 150 °C anneal. Electroless Au contacts became ohmic at a lower anneal temperature, usually 100 °C, while HgTe contacts required anneal temperatures in the 140–150 °C range. However, HgTe contacts are much more reproducible because they adhere well to HgCdTe. Precontact surface preparations which did not result in an oxidized HgCdTe surface produced the lowest HgTe contact resistances. Exposure of the HgTe surface to a short ion mill caused type conversion of the HgCdTe and therefore highly resistive and rectifying contacts.