Development of Blocked-Impurity-Band-Type Ge Detectors Fabricated with the Surface-Activated Wafer Bonding Method for Far-Infrared Astronomy

• DOI: 10.1007/s10909-016-1484-1
• Publication Date: 2016-01-14T16:53:06Z
• Authors: M. Hanaoka; H. Kaneda; S. Oyabu; M. Yamagishi; Y. Hattori; S. Ukai; K. Shichi; T. Wada; T. Suzuki; K. Watanabe; K. Nagase; S. Baba; C. Kochi
• Keywords: 0103 physical sciences; 01 natural sciences

We report the current status of the development of our new detectors for far-infrared (FIR) astronomy. We develop Blocked-Impurity-Band (BIB)-type Ge detectors to realize large-format compact arrays covering a wide FIR wavelength range up to 200 $$\upmu $$ m. We fabricated Ge junction devices of different physical parameters with a BIB-type structure, using the room temperature, surface-activated wafer bonding (SAB) method. We measured the absolute responsivity and the spectral response curve of each device at low temperatures, using an internal blackbody source in a cryostat and a Fourier transform spectrometer, respectively. The results show that the SAB Ge junction devices have significantly higher absolute responsivities and longer cut-off wavelengths of the spectral response than the conventional bulk Ge:Ga device. Based upon the results, we discuss the optimum parameters of SAB Ge junction devices for FIR detectors. We conclude that SAB Ge junction devices possess a promising applicability to next-generation FIR detectors covering wavelengths up to $$\sim $$ 200 $$\upmu $$ m with high responsivity. As a next step, we plan to fabricate a BIB-type Ge array device in combination with a low-power cryogenic readout integrated circuit.