Dynamic current oscillations in a metal-oxide-semiconductor surface potential well

Abstract

Novel oscillatory behavior has been observed in metal-oxide-semiconductor (MOS) capacitors at low temperatures. These observations were made by applying a voltage ramp to an MOS capacitor fabricated on p-type silicon. The silicon surface was driven from accumulation, through depletion, and into the avalanche regime, repetitively. The surface potential well fills with electrons as avalanche multiplication occurs during ramp-up, and emits those electrons into the bulk silicon as the well depth decreases during ramp-down. The filling and emission processes induce displacement current oscillations, which indicates that dynamically quantized two-dimensional subbands have been observed.