High resolution CdTe detector and applications to imaging devices

Using a high quality cadmium telluride (CdTe) wafer, we formed a Schottky junction and operated the detector as a diode (CdTe diode). The low leakage current of the CdTe diode allows us to apply a much higher bias voltage than was possible with the previous CdTe detectors. For a relatively thin detector of /spl sim/0.5 mm thick, the high bias voltage results in a high electric field in the device. Both the improved charge collection efficiency and the low-leakage current lead to an energy resolution of 1.1 keV FWHM at 60 keV for a 2/spl times/2 mm/sup 2/ device and 2 keV for a 10/spl times/10 mm/sup 2/ device at 5/spl deg/C without any charge-loss correction electronics. For astrophysical applications, we have developed a an initial prototype CdTe pixel detector based on the CdTe diode. The detector has 400 pixels with a pixel size of 625/spl times/625 /spl mu/m/sup 2/. Each pixel is gold-stud bonded to a fanout board and routed to a front end ASIC to measure pulse height information for each /spl gamma/-ray photon.

[1]  T. Schlesinger,et al.  Optimal bandgap variants of Cd1−xZnxTe for high-resolution X-ray and gamma-ray spectroscopy , 1999 .

[2]  Andrew D. Holland,et al.  Cooled CdZnTe detectors for X-ray astronomy , 1999 .

[3]  H. Takamura,et al.  THERMAL TREATMENT OF CDTE SURFACES FOR RADIATION DETECTORS , 1996 .

[4]  Kunishiro Mori,et al.  Performance of a new Schottky CdTe detector for hard X-ray spectroscopy , 1997 .

[5]  Paul Siffert.  Cadmium telluride and related materials as x-ray and gamma-ray detectors: a review of recent progress , 1994, Optics & Photonics.

[6]  Bradford H. Parker,et al.  CdZnTe and CdTe detector arrays for hard X-ray and gamma-ray astronomy , 1999 .

[7]  Kazuyuki Satoh,et al.  Growth and characterization of CdTe single crystals for radiation detectors , 1999 .

[8]  C. Scheiber,et al.  CdTe and CdZnTe detectors in nuclear medicine , 2000 .

[9]  Glenn F. Knoll,et al.  Radiation Detection and Measurement, 2nd Edition , 1979 .

[10]  P. Siffert,et al.  CDTE AND CD1-XZNXTE FOR NUCLEAR DETECTORS : FACTS AND FICTIONS , 1999 .

[11]  G. Knoll.  Radiation detection and measurement , 1979 .

[12]  Yasuhiro Tomita,et al.  Performance of a new Schottky CdTe detector for hard x-ray spectroscopy , 1998, Optics + Photonics.

[13]  S. Roe,et al.  Si pad detectors , 1996 .

[14]  Kazuyuki Hirose,et al.  High-resolution Schottky CdTe diode for hard X-ray and gamma-ray astronomy , 1999 .

[15]  Israel Mardor,et al.  CdTe and CdZnTe gamma ray detectors for medical and industrial imaging systems , 1999 .