A STUDY OF THE METAL-SEMICONDUCTOR (N-TYPE) RECTIFYING CONTACT
ARIZONA STATE UNIV TEMPE ENGINEERING RESEARCH CENTER
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A theoretical study of metal-semiconductor N-type rectifying contacts isdeveloped. This study begins by first analyzing previous models for this type of junction. Particular attention is given to the Schottky model and to the approximations it contains. This model is then improved upon by taking into account nonuniform impurity ionization and the free electron concentration in the depletion region. Using this more exact model a theoretical expression for the differential junction capacitance is calculated. The results indicate that the junction capacitance as a function of reverse bias can be used to accurately predict the doping concentration in the semiconductor material, but does not yield a correct measurement of the equilibrium diffusion potential or barrier height. The current voltage characteristic for this type of contact is also discussed. An expression for the I-V characteristic of this junction is derived based upon a diffusion model. This expression is then improved upon by accounting for tunneling and quantum mechanical reflection of carriers at the junction.
- Solid State Physics