I. Deyhimy

GaAs charge‐coupled devices

A Schottky‐barrier‐gate buried‐channel GaAs CCD has been successfully demonstrated. A 10‐cell (30 gates) three‐phase device was operated at room temperature. The device employs a natural channel stop formed by the transfer gates extending from an n‐type active region onto a semi‐insulating GaAs substrate.A Schottky‐barrier‐gate buried‐channel GaAs CCD has been successfully demonstrated. A 10‐cell (30 gates) three‐phase device was operated at room temperature. The device employs a natural channel stop formed by the transfer gates extending from an n‐type active region onto a semi‐insulating GaAs substrate.

Reduced Geometry GaAs CCD for High Speed Signal Processing

A Schottky barrier gate GaAs CCD is described with high transfer efficiency (>0.999/transfer) and ultra-high speed (fcl.~500 MHz) operation. Predictions for maximum achievable clock frequency are made, and possible signal processing applications are discussed.

A backside‐illuminated imaging AlGaAs/GaAs charge‐coupled device

A glass‐supported, backside‐illuminated AlGaAs/GaAs heterojunction charge‐coupled device (CCD) imager is reported. The CCD structure was grown by liquid phase epitaxy on a GaAs substrate. The top epi‐layer was bonded to glass and the GaAs substrate completely removed. A ten‐pixel three‐phase Schottky gate CCD was fabricated on the glass‐supported layer. The CCD was successfully operated as a line imager with the photosignal entering through the support glass.

GaAlAs/GaAs heterojunction Schottky barrier gate CCD

A buried channel Schottky barrier gate GaAlAs/GaAs CCD is described. Device structures, fabrication techniques and results are discussed. Charge transfer efficiency of 0.9993 per transfer has been measured on these 30 gate (10 pixel) CCDs. Dark current was found to be about an order of magnitude lower in GaAlAs than in GaAs. The best Ga.78Al.22As device has between 2 to 4nA/cm2at room temperature.

Low dark current glass bonded AlGaAs/GaAs Schottky gate imaging CCD

The fabrication and characterization of a glass bonded, backside illuminated, AlGaAs/GaAs heterojunction CCD imager is reported. The dark current of these devices is found to be <1 nA/(cm²which indicates that the glass bonding procedure does not adversely effect the dark current device performance. To isolate process induced degradation of the CCD Schottky gates, diodes were fabricated on n-Al<inf>x</inf>Ga<inf>1-x</inf>As (0 ≤ × ≤ 0.55) by e-beam evaporation of Cr/AuGe, Ti/Pt/Au and Cr/Au. The data indicate that φ<inf>Bn</inf>(Cr) ≤ φ<inf>Bn</inf>(Ti) for all solid compositions examined. Low temperature annealing causes a degradation of the Cr/AuGe and Ti/Pt/Au devices; however, the characteristics of the Cr/Au diodes improve significantly

Gaas Integrated Circuits And Charge-Coupled Devices For High Speed Signal Processing

The superior electronic properties of GaAs, as compared with silicon, make possible the achievement of much higher performance levels in GaAs signal processing devices than have been demonstrated with silicon. Only recently, however, have advances in GaAs materials and processing technology made possible the fabrication of such devices as sub-100 ps propagation delay, high density planar GaAs in-tegrated circuits with large-scale integration (LSI) compatible power levels,1 and high transfer efficiency GaAs charge-coupled devices2 which should be capable of multi-gigahertz clocking rate operation. These high performance device technologies should have major impact on the high speed signal processing area, making possible, through their much higher speeds and lower power requirements, system approaches which could not be practically realized with existing silicon technology. In this paper the advantages of GaAs for high speed signal processing are reviewed and laboratory results obtained with high speed GaAs devices are reported.

High speed GaAs CCD

A GaAs CCD with high transfer efficiency is described and implications for high speed devices fabricated with this technology are described.