Study of the conduction mechanism and the electrical response of strained nano-thin 3C-SiC films on Si used as surface s
- PDF / 653,258 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 72 Downloads / 170 Views
1129-V04-20
Study of the conduction mechanism and the electrical response of strained nano-thin 3CSiC films on Si used as surface sensors Ronak Rahimi1, Christopher M. Miller1, Alan Munger2, Srikanth Raghavan1, C. D. Stinespring3 and D. Korakakis 1, 4 1
Lane Department of Computer Science and Electrical Engineering, West Virginia University, Morgantown, WV 26506-6109 2 Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV 26506-6106 3 Department of Chemical Engineering, West Virginia University, Morgantown, WV 26506-6102 4 National Energy Technology Laboratory, 3610 Collins Ferry Road, Morgantown, WV 265070880 ABSTRACT Various superior properties of SiC such as high thermal conductivity, chemical and thermal stability and mechanical robustness provide the basis for electronic and MEMS devices of novel design [1]. This work evaluates heterostructures that consist of a few nanometers-thick 3C-SiC films on silicon substrates. Nano-thin SiC films differ significantly in their electrical behavior compared to the bulk material [2], a finding that gives rise to a potential use of these films as surface sensors. To gain a better understanding of the effect of surface states on the electrical response of these thin, strained films, several metal-semiconductor-metal heterostructures have been examined under variable conditions. The nano-thin, strained films were grown using gas source molecular beam epitaxy. Reflection high-energy electron diffraction patterns obtained from several 3C-SiC films indicate that these films are strained nearly 3% relative to the SiC lattice constant. Al, Cr and Pt contacts to a nano-thin film 3C-SiC were deposited and characterized. I-V measurements of the strained nano-thin films demonstrate metal-semiconductor-metal characteristics. Band offsets due to biaxial tensile strain introduced within the 3C-SiC films were calculated and band diagrams incorporating strain effects were simulated. Electron affinity of 3C-SiC has been extracted from experimental I-V curves and is in good agreement with the value that has been calculated for a strained 3C-SiC film [3]. On the basis of experimental and simulation results, an empirical model for the current transport has been proposed. Fabricated devices have been characterized in a controlled environment under hydrogen flow and also in a reactive ambient, while heating the sample and oxidizing the surface, to investigate the effects of the environment on the surface states. Observed changes in I-V characteristics suggest that these nano-thin films can be used as surface sensors. INTRODUCTION In multilayer semiconductor structures, stress and strain may be introduced due to differences in the lattice constants and thermal expansion coefficients of materials. As long as the thickness of the grown layers remains below the critical thickness [4], the grown films will be strained. In contrast, if the thickness of the layers is beyond the critical thickness, strain will be relaxed. Misfit dislocations which are the result o
Data Loading...
