Study of P-N Junctions and Metal-to-Metal Interfaces

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Ellison, Jeffrey
Various P-N junctions (Si/Ge, power/signal diodes) and metal-to-metal interfaces are studied using a voltage controlled current source built using off-the-shelf components. Use of a voltage controlled current source eliminates common mode interferences and allows precise measurements of I-V characteristics. Further the design of a voltage controlled current source allows for the addition/superposition of a small AC (sine wave 13.0 Hz) current to a slow varying DC current (triangular wave 0.01 Hz), which is used to obtain the dynamic conductance ( of the junction and its dependence on the junction voltage. For the diodes, both current vs. voltage and the conductance vs. voltage, exhibit switching (on/off) and hysteresis behavior between ramping up and down. The switching voltage is lower for Ge diode as compared to that of Si diode at ambient temperature and increases at For the metal-to-metal, the I-V is linear (Ohmic) with very small y-intercept and the conductance is constant down to typical metallic behavior.