TUNNELING BETWEEN A METAL AND SILICON SEPARATED BY A POLYMER INSULATOR.
Abstract
This research investigates tunneling between a metal and silicon separated by an insulator (MIS structure) and develops a model describing the MIS current-voltage characteristics. Analysis shows that any model for MIS tunneling must consider the density of surface states and the formation of a depletion or accumulation layer in the silicon. The model shows that the electric field in the insulator controls the MIS current while the charge distribution in the silicon determines the insulator field. For the experimental results presented in this report a polymerized silicone film formed the insulator. After establishing the technique of forming the polymer, metal-insulator (MIM) junctions enabled study of the electrical properties of the polymer and characterization of MIM tunneling currents. The MIM characteristics permitted comparative analysis with MIS structures. The experimental MIS curves on both N and P type silicon show the exponential dependence of current on voltage and they indicate that the mechanisms for MIM and MIS tunneling are quite similar. An asymmetric saturation of the MIS tunneling occurs. This is shown to be caused by the formation of a depletion layer on the semiconductor which forms after completely charging the surface states. Experimental evidence verified this model. The distinct roles played by the surface states, the depletion layer, insulator thickness, temperature and the work function of the field plate metal appears in the analysis. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 15, 1966
- Accession Number
- AD0807361
Entities
People
- Carl W. Wilmsen
- William H. Hartwig
Organizations
- University of Texas at Austin