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Optical characteristics of pn junctions and MOS transistors with applications to integrated circuit measurements

Optical characteristics of pn junctions and MOS transistors with applications to integrated circuit measurements
Optical characteristics of pn junctions and MOS transistors with applications to integrated circuit measurements

The photocurrent generation characteristics of pn junctions and MOS transistors are studied with a view to applying these devices to input data optically direct into the internal circuity of integrated circuits, by a finely focussed laser beam. This permits simple testing schemes for fault detection; and can make large savings in the time taken for diagnostic testing of IC's. A review of the spectral characteristics of the photocurrents of both the diffused pn junction and the MOS (induced) pn junction are presented and compared.

It is also shown that the optical input of data can be employed to measure propagation delay times associated with each stage in an MOS dynamic shift-register circuit; which leads to a better understanding of the internal operation of the circuit. 

A novel application of the MOS phototransistor is also presented. It is shown that amplification of the photocurrent generated can be produced by including a large resistance between the substrate and the source. A simple model which adequately describes the mechanisms involved is presented. Results of calculations of both the amplification factor and the response speed, based on this model show good agreement with experiment.

This configuration can be used to produce from a moderate laser beam power, the large photocurrents needed to switch some digital IC families (e.g. CMOS). 

Silicon-gate devices are very suitable as MOS phototransistors because the gate electrode transmits visible radiation. This property, coupled with photocurrent amplification where necessary, makes the laser probe method of data input in conjunction with standard test equipment a useful method for testing of present day MOS integrated circuits.

University of Southampton
Luhanga, Pearson Vincent Chitanda
7f51aa1f-1908-44b9-8276-4e8481e0f617
Luhanga, Pearson Vincent Chitanda
7f51aa1f-1908-44b9-8276-4e8481e0f617
Smith, J.G.
e805e557-71e5-4da8-bce0-6093ed2b2db0

Luhanga, Pearson Vincent Chitanda (1981) Optical characteristics of pn junctions and MOS transistors with applications to integrated circuit measurements. University of Southampton, Doctoral Thesis, 151pp.

Record type: Thesis (Doctoral)

Abstract

The photocurrent generation characteristics of pn junctions and MOS transistors are studied with a view to applying these devices to input data optically direct into the internal circuity of integrated circuits, by a finely focussed laser beam. This permits simple testing schemes for fault detection; and can make large savings in the time taken for diagnostic testing of IC's. A review of the spectral characteristics of the photocurrents of both the diffused pn junction and the MOS (induced) pn junction are presented and compared.

It is also shown that the optical input of data can be employed to measure propagation delay times associated with each stage in an MOS dynamic shift-register circuit; which leads to a better understanding of the internal operation of the circuit. 

A novel application of the MOS phototransistor is also presented. It is shown that amplification of the photocurrent generated can be produced by including a large resistance between the substrate and the source. A simple model which adequately describes the mechanisms involved is presented. Results of calculations of both the amplification factor and the response speed, based on this model show good agreement with experiment.

This configuration can be used to produce from a moderate laser beam power, the large photocurrents needed to switch some digital IC families (e.g. CMOS). 

Silicon-gate devices are very suitable as MOS phototransistors because the gate electrode transmits visible radiation. This property, coupled with photocurrent amplification where necessary, makes the laser probe method of data input in conjunction with standard test equipment a useful method for testing of present day MOS integrated circuits.

Text
Luhanga 1981 Thesis - Version of Record
Available under License University of Southampton Thesis Licence.
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Published date: 1981

Identifiers

Local EPrints ID: 459688
URI: http://eprints.soton.ac.uk/id/eprint/459688
PURE UUID: 665209ac-4b08-4bd4-83b8-09321ac5cded

Catalogue record

Date deposited: 04 Jul 2022 17:16
Last modified: 23 Jan 2023 18:05

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Contributors

Author: Pearson Vincent Chitanda Luhanga
Thesis advisor: J.G. Smith

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