RADIATION EFFECTS IN SILICON AND GERMANIUM.
Abstract
Measurements indicate that oxygen concentration does not affect lifetime degradation in neutron-irradiated silicon. Type and amount of dopant is also unimportant in n-type material and plays only a limited role in p-type silicon with resistivities less than approximately 5 ohm-cm. The dependence of lifetime on both carrier concentration and temperature indicates that simple recombination theory is not followed; alternate possibilities for explaining the results are proposed. Carrier concentration and mobility in neutron-irradiated silicon are more seriously affected by oxygen, dopant, and possibly other factors, especially in n-type material. The dominance of the 'disordered region' in recombination is indicated in several ways, including behavior of short-term annealing. Measurement of the dependence of lifetime on injection level has proved very effective in obtaining recombination level parameters. The dominant recombination level at low excitation in both neutron- and gamma-irradiated germanium has been found to be E sub r - E sub v = 0.34 eV with almost no dependence on dopant. Evidently the effective energy level position of the recombination center is unaffected by the disordered region. A second level at E sub c - E sub r approximately 0.2 eV is required to explain the dependence of lifetime on injection level at high excitation. Comparison with measurements of the temperature dependence of lifetime indicates a temperature variation of electron capture probability. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1966
- Accession Number
- AD0643268
Entities
People
- C. A. Germano
- O. L. Curtis
- R. F. Bass