Hughes Aircraft Company

Hughes Electronics Corporation

Robert Baron

Le Thanh Pham

John P Sheppard

Charles B Zarowin

William R Peterson

A plasma assisted chemical transport system for additive or subtractive shaping of a substrate surface employs a plasma head (30) that generates a plasma (34) and is caused to scan the surface of a workpiece (51) to provide selective shaping, either by etching or depositing material. Corrosive gases of the plasma are isolated to minimize corrosive effects on the drive mechanism (20) by encompassing the plasma head within a flexible bellows (64). Scanning is in a circular path of varying radius. Acceleration induced vibrations caused by programmed varying scan velocity are avoided by use of an oppositely rotation body (56) of equal torsional inertia. Effects of linear acceleration in the radial direction are effectively avoided by making rotational scan velocity many times greater than radial scan velocity. Errors due to singularity that could exist when the scanning plasma head is at the center of its scan are kept within acceptable tolerances by stopping the scan when the center of the scanning head (30) is at a distance .DELTA.r from the center of the scan path that is equal to incremental radial steps between successive circular scan paths.

Plasma assisted chemical transport method and apparatus

The photo-sensitive detector region of conventional Impurity Band Conduction (IBC) detector (also known as a Blocked Impurity Band [BIB] detector) is divided into a wide detection (or collection) region and a narrow gain region by means of tailoring the doping profile. The narrow gain region is that portion of the photo-sensitive detector region closest to the blocking layer, where the electric field is the largest, whose As concentration is made smaller (in the range of 2 to 5.times.10.sup.17 cm.sup.-3) to increase the impact ionization coefficient by decreasing the electron scattering. The wide detection region is that portion of the photo-sensitive detector region furthest from the blocking layer, where the electric field is smallest and the As concentration is larger (in the range of 5 to 8.times.10.sup.17 cm.sup.-3) to decrease the impact ionization coefficient by increasing the electron scattering.

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Santa Monica, CA, United States of America

Robert Baron