High-purity germanium crystal growing
The germanium crystals used for the fabrication of nuclear radiation detectors are required to have a purity and crystalline perfection which is unsurpassed by any other solid material. These crystals should not have a net electrically active impurity concentration greater than 10/sup 10/cm/sup -3/ and be essentially free of charge trapping defects. Such perfect crystals of germanium can be grown only because of the highly favorable chemical and physical properties of this element. However, ten years of laboratory scale and commercial experience has still not made the production of such crystals routine. The origin and control of many impurities and electrically active defect complexes is now fairly well understood but regular production is often interrupted for long periods due to the difficulty of achieving the required high purity or to charge trapping in detectors made from crystals seemingly grown under the required conditions. The compromises involved in the selection of zone refining and crystal grower parts and ambients is discussed and the difficulty in controlling the purity of key elements in the process is emphasized. The consequences of growing in a hydrogen ambient are discussed in detail and it is shown how complexes of neutral defects produce electrically active centers.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6860175
- Report Number(s):
- LBL-14916; CONF-821107-39; ON: DE83004181
- Resource Relation:
- Conference: 6. international symposium on the scientific basis for radioactive waste management, Boston, MA, USA, 1 Nov 1982; Other Information: Portions of document are illegible
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
GERMANIUM
CRYSTAL GROWTH
HIGH-PURITY GE DETECTORS
FABRICATION
CRYSTAL DEFECTS
IMPURITIES
PURIFICATION
ZONE REFINING
CRYSTAL STRUCTURE
ELEMENTS
GE SEMICONDUCTOR DETECTORS
MEASURING INSTRUMENTS
METALS
PROCESSING
RADIATION DETECTORS
REFINING
SEMICONDUCTOR DETECTORS
SEPARATION PROCESSES
440101* - Radiation Instrumentation- General Detectors or Monitors & Radiometric Instruments
360601 - Other Materials- Preparation & Manufacture