FTIR and electrical characterization of a-Si:H layers deposited by PECVD at different boron ratios

Abstract

Hydrogenated amorphous silicon (a-Si:H) has found applications in flat panel displays, photovoltaic solar cell and recently has been employed in boron doped microbolometer array.Wehave performed electrical and structural characterizations of a-Si:H layers prepared by plasma enhanced chemical vapor deposition (PECVD) method at 540K on glass substrates at different diborane (B2H6) flow ratios (500, 250, 150 and 50 sccm). Fourier transform infrared spectroscopy (FTIR) measurements obtained by specular reflectance sampling mode, show Si–Si, B–O, Si–H, and Si–O vibrational modes (611, 1300, 2100 and 1100cm−1 respectively) with different strengths which are associated to hydrogen and boron content. The current–voltage curves show that at 250 sccm flow of boron the material shows the lowest resistivity, but for the 150 sccm boron flow it is obtained the highest temperature coefficient of resistance (TCR). © 2010 Elsevier B.V. All rights reserved.