Measurement of thickness of high-resistivity substrate by photoconduction enhanced capacitance displacement sensor

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Capacitive displacement sensors provide non-contact, extreme resolution, and absolute accuracy thickness measurements. However, if the resistivity of a target substrate is within 105-107 ohm-cm, an uncertainty will appear in the thickness measurement. The common solution is to adjust the resistivity to be outside the range by implanting dopants and followed by an activation anneal, but this will unavoidably lead to changes in the material properties and morphology. Here, we exploit the photoconductive effect to generate sufficient high number of electron-hole pairs, thereby temporarily decreasing the resistivity and thus enabling the capacitive displacement sensor to accurately measure the thickness at nanoscale resolution. After the measurement is complete, the resistivity of the substrate will return to its original status. The photoconductive effect can be simply induced via light irradiation at the sensing point, which narrows or eliminates the gap in the measurement range of capacitive sensors to include high-resistivity substrate.

Original languageEnglish
Title of host publicationSelected Proceedings from the 231st ECS Meeting New Orleans, LA - Spring 2017
PublisherElectrochemical Society Inc.
Pages1747-1752
Number of pages6
Edition11
ISBN (Electronic)9781607688174
ISBN (Print)9781623324605
DOIs
StatePublished - 2017
Event231st ECS Meeting - New Orleans, United States
Duration: 28 May 20171 Jun 2017

Publication series

NameECS Transactions
Number11
Volume77
ISSN (Print)1938-6737
ISSN (Electronic)1938-5862

Conference

Conference231st ECS Meeting
Country/TerritoryUnited States
CityNew Orleans
Period28/05/171/06/17

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