Development of Low Stress Ohmic Contacts to HgCdTe

We will manufacture novel ohmic contacts and measure the stress in the ohmic contacts by several methods. We will thermally cycle the ohmic contacts and look for nucleated dislocations as a measure of induced stress. In addition we will evaluate an approach of using a new spectroscopy technique for measuring stress in semiconductors. We will also coordinate our work with Enrico Bellotti from Boston University who is an expert at computer modeling of physical phenomena. He will model the strain field in the crystal and will make predictions of how the strain field will interact and affect the electrical properties. We will use CTLMs to measure IVs. We will measure the ohmics at room temperature and at cryogenic temperatures. We will perform thermal cycling of the ohmic contacts to see how the ohmics behave under thermal stress. We will bump-bond the CTLM patterns to a fan-out board and make measurements in a standard dewar at cryogenic temperatures. Supporting Photronix in this effort is BAE SYSTEMS. BAE SYSTEMS has agreed to donate longwave LPE infrared double layer material as well as full use of its extensive infrared processing facility.