NISCAIR Online Periodicals Repository

Research Journals >
Indian Journal of Pure & Applied Physics (IJPAP) >
IJPAP Vol.45 [2007] >
IJPAP Vol.45(11) [November 2007] >

Title: Anomaly in optical thickness monitoring of a quarterwave thin film multilayer stack — Its cause and how to avoid it
Authors: Basu, A
Keywords: Optical thickness monitoring
Thin film
Multilayer stack
Turning points
Refractive index
Issue Date: Nov-2007
Publisher: CSIR
IPC CodeG01B11/06, G01B15/02, G01B21/00 121:02
Abstract: During the optical monitoring of a quarterwave thin film optical multilayer stack being deposited sequentially on a substrate in a deposition chamber, the intensity of the light beam transmitted through or reflected from the monitoring plate goes through a series of turning points (maxima and minima). The deposition of a film is stopped at a turning point in order to obtain a quarterwave thick film at the monitoring wavelength. In most of the cases, the maxima and minima occur sequentially. However, during the deposition of some quarterwave multilayer stacks a maximum is not followed by a minimum (or vice versa) during the deposition of successive films. Rather, the intensity may change slightly in the opposite direction to that which is expected or not change appreciably, making the monitoring of the deposited film thickness difficult, if not impossible. This occurs when the effective refractive index of the multilayer stack is very close to the refractive index of the film to be deposited next. Either an alternative method of monitoring the thickness of that particular film has to be adopted, or fresh monitoring plates have to be used at crucial stages during the sequential deposition of the multilayer stack.
Page(s): 920-925
ISSN: 0019-5596
Source:IJPAP Vol.45(11) [November 2007]

Files in This Item:

File Description SizeFormat
IJPAP 45(11) 920-925.pdf169.43 kBAdobe PDFView/Open
 Current Page Visits: 742 
Recommend this item


Online Submission of Articles |  NISCAIR Website |  National Knowledge Resources Consortium |  Contact us |  Feedback

Disclaimer: NISCAIR assumes no responsibility for the statements and opinions advanced by contributors. The editorial staff in its work of examining papers received for publication is helped, in an honorary capacity, by many distinguished engineers and scientists.

CC License Except where otherwise noted, the Articles on this site are licensed under Creative Commons License: CC Attribution-Noncommercial-No Derivative Works 2.5 India

Copyright © 2015 The Council of Scientific and Industrial Research, New Delhi. All rights reserved.

Powered by DSpace Copyright © 2002-2007 MIT and Hewlett-Packard | Compliant to OAI-PMH V 2.0

Home Page Total Visits: 167028 since 01-Sep-2015  Last updated on 28-Jun-2016Webmaster: