Optoelectronic and structural properties of a-Ge1−xCx:H prepared by rf reactive cosputtering

Optoelectronic, structural, and mechanical properties of hydrogenated amorphous germanium carbon (a-Ge1−xCx:H) alloys are presented. The films were prepared by the rf cosputtering technique using graphite-germanium composite targets. Films with carbon contents in the 0<x<1 range were prepared under the same conditions used to obtain a-Ge:H films with good optoelectronic properties. The trends of the optical gap, infrared absorption, dark conductivity, and mechanical stress as a function of the carbon content suggest that the properties of films with low carbon concentration are mainly controlled by the incorporation of sp3 hybridized carbon. These films have good optoelectronic and structural properties. As the carbon content increases, the properties of the films are determined by the concentration of sp2 carbon sites.

[1]  A. Thanailakis,et al.  Amorphous (SiC)xGe1−x :H films prepared by rf sputtering: Optical and electrical properties , 1987 .

[2]  G. Connell,et al.  Use of hydrogenation in structural and electronic studies of gap states in amorphous germanium , 1976 .

[3]  J. Shinar,et al.  An IR, optical, and electron-spin-resonance study of as-deposited and annealed a-Ge1−xCx:H prepared by rf sputtering in Ar/H2/C3H8 , 1987 .

[4]  F. C. Marques,et al.  Use of hydrogenation in the study of the properties of amorphous germanium tin alloys , 1989 .

[5]  Zanatta,et al.  Transport properties of nitrogen-doped hydrogenated amorphous germanium films. , 1992, Physical review. B, Condensed matter.

[6]  R. Grigorovici,et al.  Optical Properties and Electronic Structure of Amorphous Germanium , 1966, 1966.

[7]  S. Jones,et al.  Stress measurement of glow discharge produced a-Ge:H thin films and its relation to electronic and structural properties , 1991 .

[8]  M. DiDomenico,et al.  Behavior of the Electronic Dielectric Constant in Covalent and Ionic Materials , 1971 .

[9]  M. Cardona.  Vibrational Spectra of Hydrogen in Silicon and Germanium , 1983 .

[10]  B. Schröder,et al.  Vibrational, optical and electronic properties of the hydrogenated amorphous germanium-carbon alloy system , 1994 .

[11]  D. Mckenzie,et al.  An electron diffraction study of amorphous hydrogenated germanium‐carbon thin films , 1990 .

[12]  A. Kellock,et al.  Absolute cross section for hydrogen forward scattering , 1992 .

[13]  R. Shinar.  Hydrogen adsorption on some a‐Ge1−xCx:H films prepared by radio‐frequency sputtering , 1988 .

[14]  F. C. Marques,et al.  Stress and Elastic Constants of Amorphous Germanium Nitrogen Alloys , 1995 .

[15]  M. Kumru.  A comparison of the optical, IR, electron spin resonance and conductivity properties of a-Ge1−xCx:H with a-Ge:H and a-Ge thin films prepared by r.f. sputtering , 1991 .

[16]  G. Urban,et al.  Deposition and properties of germanium-carbon alloy films produced from tetraethylgermanium in an r.f. discharge , 1990 .

[17]  J. Shinar,et al.  The interaction of oxygen molecules with amorphous Ge, Ge:H, and some Ge:C:H alloys , 1989 .

[18]  Thèye,et al.  Influence of annealing on the hydrogen bonding and the microstructure of diamondlike and polymerlike hydrogenated amorphous carbon films. , 1995, Physical review. B, Condensed matter.

[19]  William D. Nix,et al.  Stresses and deformation processes in thin films on substrates , 1988 .

[20]  D. Meissner,et al.  Electrical conductivity of amorphous hydrogenated carbon , 1995 .

[21]  N. Saito,et al.  Preparation of a‐SiC:H/a‐GeC:H superlattices by dual magnetron sputtering , 1989 .

[22]  F. C. Marques,et al.  Structural, optical, and electrical characterization of improved amorphous hydrogenated germanium , 1990 .

[23]  R. Swanepoel.  Determination of the thickness and optical constants of amorphous silicon , 1983 .

[24]  R. S. Williams,et al.  Synthesis by laser ablation and characterization of pure germanium-carbon alloy thin films , 1993 .

[25]  D. Anderson,et al.  Electrical and optical properties of amorphous silicon carbide, silicon nitride and germanium carbide prepared by the glow discharge technique , 1977 .

[26]  Tatsuo Shimizu,et al.  ESR studies on sputtered amorphous SiC, SiGe and GeC films , 1981 .

[27]  G. Turban,et al.  Infrared absorption of hydrogenated amorphous SiC and GeC films , 1980 .

[28]  Sunil Kumar,et al.  Thin films of amorphous germanium-carbon and germanium-nitrogen alloys prepared by activated reactive evaporation , 1990 .

[29]  N. Saito,et al.  Comparative study of properties between a‐GeC:H and a‐SiC:H films prepared by radio‐frequency reactive sputtering in methane , 1995 .

[30]  Sunil Kumar,et al.  Structure and transport properties of amorphous Ge1−xCx:H thin films obtained by activated reactive evaporation , 1988 .

[31]  Xin Jiang,et al.  The study of mechanical properties of a‐C:H films by Brillouin scattering and ultralow load indentation , 1989 .

[32]  John Robertson,et al.  Influence of ion energy and substrate temperature on the optical and electronic properties of tetrah , 1997 .

[33]  Tatsuo Shimizu,et al.  Annealing and crystallization processes in tetrahedrally bonded binary amorphous semiconductors , 1984 .

[34]  J. Bullot,et al.  Physics of Amorphous Silicon–Carbon Alloys , 1987 .

[35]  J. Robertson.  Hard amorphous (diamond-like) carbons , 1991 .

[36]  N. Saito,et al.  Influence of deposition conditions on the properties of a-GeC:H and a-Ge:H films prepared by r.f. magnetron sputtering , 1995 .