The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Properties of sputtered a-Ge and a-Ge : H thin films
Author:	Cho, Hanjin
View Online:	njit-etd1987-008 ([12], 63 pages ~ 2.6 MB pdf)
Department:	Department of Electrical Engineering
Degree:	Master of Science
Program:	Electrical Engineering
Document Type:	Thesis
Advisory Committee:	Sohn, Kenneth (Committee chair) Cornely, Roy H. (Committee member) Ball, W. H. Warren (Committee member)
Date:	1987
Keywords:	Amorphous semiconductors. Thin films --Electric properties. Germanium --Electric properties.
Availability:	Unrestricted
Abstract:	The effect of the amorphous and glassy structure of amorphous germanium films on their electrical characteristics was investigated experimentally. The films were deposited onto silicon substrates using a modified MRC 8800 triode sputtering system. The Poole-Frenkel and Schottky mechanisms are discussed in detail and the shortcomings of the accepted picture of the former in amorphous materials are dealt with. It was concluded on the basis available evidence that the current flow in amorphous germanium favors the Poole-Frenkel mechanism at high fields. Amorphous hydrogenated germanium films which were deposited by bias sputtering were characterized by measuring the infrared absorption. The films have absorption peaks,as expected, at 1950 cm-1 and at 570 cm-1 due to GeH2 bonding and at 1880 cm-1 due to GeH2 bonding. A method was described for determining the optical constants of a thin film deposited on a nonabsorbing window using a single set of transmittances over an absorption band. The method depends on the fact that the phase shift of the transmitted radiation can be determined from the transmittance by a Kramers-Kronig transform. The transmittance data of a-Ge:H and sputtered silicon nitride films were used to calculate their optical constants by this method. In a-Ge:H films, the value of the calculated refractive index in the k=0 region was not reasonable. However, for Si3N4 films, the calculated absorption coefficient was consistent with the experimental results.