Ohmic Contact For Cdznte Crystal Preparation Process And Properties Of Thin Film Electrode

Cd1-xZnxTe crystal has been proved to be the most excellent material to detect X ray and gamma ray since the 90 ages in 20th century. Compared with the traditional NaI scintillator probe, Cd1_xZnxTe probe has higher detecting efficiency and power resolution, and can be widely used in fields such as security monitor, industrial flaw detection, medical diagnosis, celestial body X ray telescope and so on. One of the most key technologies of preparing Cd1-xZnxTe detector is to make ohmic contact film electrode on Cd1-xZnxTe crystal's surface, and the main technology usually used is evaporation, but the cohesion of evaporated film isn't very firm. For the purposes to make Cd1-xZnxTe detector, ohmic contact materials of Cd1-xZnxTe crystal are selected and structure of electrode is designed. The processing of conducting film prepared by the magnetron sputtering is studied. The main results are listed as follow:The contact relationship between metal and Cd1-xZnxTe is analyzed theoretically, finding that the main factors affecting ohmic contact are power functions of metal and semiconductor, and surface layer effective states as well, and meanwhile illustrating the laws of factors affecting on the contact resistance. Accordingly, materials and construction of electrode film are designed.Using JGP560C magnetron sputtering equipment, Cu/Ag film are deposited on Cd1-xZnxTe substrate by DC magnetron sputtering in order to get the influences of the main experiments parameters such as sputtering power, gas flow, vacuum air pressure, magnetoelectricity power and substrate temperature on deposition rate of film, discovered that DC sputtering power is the most key factor influencing the deposition rate. Deposition rate is increase quickly with sputtering power.The purity of film deposited by RF magnetron sputtering is very high, and the reason that impurities exist in the film deposited by DC magnetron sputtering is analyzed. Thickness, impurities and micro construction of film has notable influenceto resistance of film, especially the impurities. How sputtering power, substrate temperature and gas flow influenced the properties of cohesion are studied. Results show that the increase of sputtering power has positive affection.