Effects of surface oxides on field emission from silicon

This report documents energy distribution measurements of field emission from single-tip Si field emitter arrays. The emission energy distributions are much broader than clean metal distributions, extending several volts below the Fermi level and often including multiple peak structure. The peak positions typically move to lower energy as the gate voltage is increased, however, the emission history as well as the emission current and/or gate voltage can change the energy as well as intensity of the energy distributions. Changes in the distribution including shifts to higher energy occur suddenly and spontaneously as well as slowly during emission. These results show that the emission comes from oxide and interface states, which refill at a finite rate, limiting the emission current. Changes in the local electric potential due to single charges becoming trapped in the oxide account for large and discrete changes in the emission distribution. [S0734-211X(00)07603-6].