Advanced Silicon Material Development for LADIR
Abstract
Results from several float-zoned <100> Si:Ga crystals show that the uniformity of Ga distribution improves as the growth rate is decreased and the rotation rate during growth is increased, in agreement with diffusion theory. For 2-in. diameter crystals, the lowest growth rate that will yield dislocation- free crystals in our equipment is about 3 mm/min. The onset of mechanical resonance and vibration of the growing crystal supported on its slender seed crystal limits the rotation rate of about 10 rpm. Crystals grown under these conditions, and later neutron transmutation counterdoped, show very good spatial uniformity of both major and compensating dopants. Thermal diffusion studies showed that annealing at 1300 C for several hundred hours also reduced Ga concentration fluctuations. Longitudinal detectors were fabricated from processed FPA wafers covering a Ga concentration range from 0.2 to 2 x 10 to the 17th power Ga atoms/cu cm. Experimentally determined quantum efficiency and D* for these detectors agreed very well with theoretical predictions based on a model developed by Baron and Szmulowicz. The value of this model to future FLIR system design is now firmly established.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1981
- Accession Number
- ADA120980
Entities
People
- G. D. Robertson
- H. Kimura
- M. H. Young
- O. J. Marsh
Organizations
- HRL Laboratories