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/(cm
²
which 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
x
Ga
1-x
As (0 ≤ × ≤ 0.55) by e-beam evaporation of Cr/AuGe, Ti/Pt/Au and Cr/Au. The data indicate that φ
Bn
(Cr) ≤ φ
Bn
(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