Hydrogen-induced mechanical properties of amorphous silicon thin films

Shaik, Habibuddin and Rao, Mohan G (2015) Hydrogen-induced mechanical properties of amorphous silicon thin films. In: MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING, 38 . pp. 165-170.

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Abstract

Mechanical properties of thin films such as residual stress and hardness are of paramount importance from the device fabrication point of view. Intrinsic stress in sputtered films can be tensile or compressive as decided by the number density and the energy of the plasma species striking the growing film. In the presence of hydrogen we analyzed the applicability of idealized stress reversal curve for amorphous silicon thin films deposited by DC, pulsed DC (PDC) and RF sputtering. We are successfully able to correlate the microstructure with the stress reversal and hardness. We observed a stress reversal from compressive to tensile with hydrogen incorporation. It was found that unlike in idealized stress reversal curve case, though the energy of plasma species is less in DC plasma, DC deposited films exhibit more compressive stress, followed by PDC and RF deposited films. A tendency towards tensile stress from compressive stress was observed at similar to 13, 18 and 23 at%H for DC, PDC and RF deposited films respectively, which is in exact agreement with the vacancy to void transition in the films. Regardless of the sputtering power mode, the hardness of a-Si:H films is found to be maximum at C-H similar to 10 at%H. Enhancement in hardness with C-H (up to C-H similar to 10 at%H) is attributed to increase of Si-H bonds. Beyond C-H similar to 10 at%H, hardness starts falling. (C) 2015 Elsevier Ltd. All rights reserved.

Item Type:	Journal Article
Publication:	MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
Publisher:	ELSEVIER SCI LTD
Additional Information:	Copy right for this article belongs to the ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND
Keywords:	Internal stress; Hardness; Amorphous silicon; Sputtering; Ion energy and plasma
Department/Centre:	Division of Physical & Mathematical Sciences > Instrumentation Appiled Physics
Date Deposited:	12 Aug 2015 04:24
Last Modified:	12 Aug 2015 04:24
URI:	http://eprints.iisc.ac.in/id/eprint/52092

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