PbTe Flash Evaporation on Si <100> Substrates for Heterojunction Infrared Detectors
INSTITUTO DE AERONAUTICA E ESPACO SAO JOSE DOS CAMPOS (BRAZIL)
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This work is to present results of flash evaporation of PbTe directly over single crystals p-type Si substrates, in order to produce heterojunction infrared detectors HIRD, working at 4.3 micrometers IR wavelength. The evaporation was performed on modified JEOL vacuum equipment, model JEE4B a, working with vacuum pressure around 10exp -5 torr, using diffusion pump. The HIRDs produced with this method presented the same detectivity D values of HIRDs made with Hot Wall Epitaxial System HWE b, in which PbTe epitaxial layers were grown directly over the same Si substrates, where an ionic pump reached about 10exp -9 torr as vacuum pressure. The best results. were obtained with PbTe layers grown with Molecular Beam Epitaxial MBE method c directly over Si substrates, where the vacuum pressure is around 10exp -9 torr, also using an ionic pump. The advantage of growing PbTe directly over Si wafers is that the HIRDs perform at room temperature. The detectivity values of HIRDs obtained with methods a and b, were D approx. 4, 8 x 10exp 5 cm.Hzsup 12W and with method c, D approx. 6, 7 x 10exp 6 cm.Hzsup 12W. Different technologies a very low costs, c high technology not very different results.
- Infrared Detection and Detectors
- Solid State Physics