Research On Technology Of Novel Terahertz Blocked Impurity Band Detectors

Blocked impurity band(BIB)detectors can detect the terahertz radiation from 30 ?m to 300 ?m,which has higher quantum efficiency,longer response wavelength and better radiation resistance than traditional photoconductivity.In order to detect astronomical objects with characteristics of wide-spectrum,low background and weak signal,the material and technology for BIB detectors have been continuously being developed.This paper introduces the design of two kinds of detectors with different structures and the related technology.Firstly,this thesis summarizes the current status and progress on material and structure of BIB detectors.Secondly,the related technology,the device structure and working principle of BIB detectors are well-covered.Finally,this study provides the design and preparation process of epitaxial and planar GaAs BIB detectors.And planar GaAs BIB detectors are tested.The research on technology of planar GaAs blocked impurity band detectors includes: the device structure of planar GaAs BIB detectors,analysis of parameter design of GaAs BIB detectors,the preparation process of planar GaAs BIB detectors,and simulation of ion implantation schemes for absorbing region and contact layer.The results show that the implanted Si ions with different energy and different doses four times in succession could achieve uniform distribution of doping impurities in the absorbing region and contact region.The final implantation depth is about 1 ?m,and the doping concentration is 5×1015 cm-3 and 4×1019 cm-3 respectively?The research on technology of epitaxial GaAs blocked impurity band detectors includes: the investigation of the current status of Ga As epitaxial growth technology and the choice of metal organic chemical vapor deposition(MOCVD)for preparing GaAs epitaxial wafers,the design of the device structure and the related fabrication processes of epitaxial GaAs BIB detectors,as well as several key technologies research and improvement.The preparation method of the ohmic electrode is analyzed.The Au-Ge-Ni metal system is selected and the wafer is subjected to rapid thermal annealing with the polishing surface facing down.The annealing process of GaAs BIB detectors and Si BIB detectors is compared and analyzed.The GaAs etching process is researched and improved,and finally,SiO2 prepared by plasma enhanced chemical vapor deposition(PECVD)is used as a mask for the process.Finally,the fabricated BIB detectors are tested.The results show that GaAs:Si BIB detectors have a response in the range of 60~200 ?m(5~1.5 THz),which completely falls in the terahertz frequency band.