Piezoresistor Sensor Fabrication by Direct Laser Writing on Hydrogenated Amorphous Silicon. Issue 1594 (13th March 2014)

• Record Type: Journal Article
• Authors: Alpuim, P.; Cerqueira, M.F.; Junior, G.; Gaspar, J.; Borme, J.
• Is Part Of: MRS proceedings. Issue 1594:(2014)
• Publication Date: 2014-03-13
• Subjects: Electrical engineering -- Congresses; Physics -- Congresses; Materials -- Research -- Congresses; Materials science -- Congresses; 620.11
• DOI: 10.1557/opl.2014.296
• Languages: English
• ISSNs: 0272-9172

Abstract

<abstract abstract-type="normal"> <title>ABSTRACT</title> <p>In this paper we report on the 532 nm Nd:YAG laser-induced crystallization of 10 nm thick boron-doped hydrogenated amorphous silicon thin films deposited on flexible polyimide and on rigid oxidized silicon wafers by hot-wire or by plasma-enhanced chemical vapor deposition. The dark conductivity increased from ∼10^-7 Ω^-1cm^-1, in the as-deposited films, to ∼10 and 50 Ω^-1cm^-1 after laser irradiation, on rigid and flexible substrates, respectively. Depending on type of substrate, laser power and fluence, a Raman crystalline fraction between 55 and 90 % was measured in HWCVD films, which was higher than observed in rf-PECVD films (35-55 %). Crystallite size remained small in all cases, in the range 6-8 nm. Due to a very high conductivity contrast (&gt;7 orders of magnitude) between amorphous and crystallized regions, it was possible to define conductive paths in the a-Si:H matrix, by mounting the sample on a X-Y software-controlled movable stage under the laser beam, with no need for the usual lithography steps. The resistors scribed by direct laser writing had piezoresistive properties, with positive gauge factor ∼1. The details of the laser interaction process with the Si film were revealed by scanning electron microscopy imaging.</p> </abstract>