## Digitized Theses

1987

Dissertation

#### Degree Name

Doctor of Philosophy

#### Abstract

This work investigated the physical properties and fabrication feasibility of charge coupled devices (CCDs) and charge injection devices (CIDs) using nMOS integrated circuit design and fabrication techniques. Devices for both signal processing and optical imaging applications were designed, fabricated and analyzed. These latter circuits included both those using MOS gate regions and those using separate sensor diode areas for optical signal detection.;Sample CCDs and CIDs were designed in accordance with lambda based integrated circuit layout rules and fabricated using a two polysilicon layer nMOS process supplied through the facilities of Northern Telecom Electronics (Ottawa, Canada) and the Canadian Microelectronics Corporation (Kingston, Canada). The devices were optimized for signal and image processing tasks and testing of the fabricated samples centred on data relevant to these applications.;In designing the devices an overlapping gate structure was employed which reduced charge transfer losses to a negligible level and freed the devices of non-linear signal distortion. The large gate oxide capacitances {dollar}(3.5 \times 10\sp{lcub}-4{rcub}{dollar} Fm{dollar}\sp{lcub}-2{rcub}){dollar} provided by the nMOS process allowed signal charges in the 10{dollar}\sp{lcub}-12{rcub}{dollar} C range to be stored while using small gate areas (10{dollar}\sp{lcub}-9{rcub} {lcub}\rm m{rcub}\sp 2){dollar} and TTL compatible clock signal voltages. Maximum signal storage times were limited by the dark charge generation rate, which was measured as {dollar}1.6 \times 10\sp{lcub}-4{rcub}{dollar} C m{dollar}\sp{lcub}-2{rcub}{dollar} s{dollar}\sp {lcub}-1{rcub}{dollar} at T = 293 K. Surface state trap density was {dollar}2 \times 10\sp{lcub}14{rcub}{dollar} m {dollar}\sp 2{dollar} eV{dollar}\sp{lcub}-1{rcub}{dollar} resulting in a charge transfer inefficiency of up to {dollar}1.0 \times 10\sp{lcub}-2{rcub}{dollar} per stage for the CCDs.;The spectral response characteristics of the optical imaging circuits showed excellent response linearity with respect to the incident light intensity and exposure time. Quantum efficiencies in the range {dollar}\eta{dollar} = 0.21 to {dollar}\eta{dollar} = 0.35 were achieved without additional optical matching.

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