Electron Injection into the Gate Oxide of MOS Structures at Liquid Nitrogen Temperature : Measurement and Simulation

Abstract
Measured electron injection probabilities (P_JN) into to the gate oxide of MOS structures [1] are presented for both liquid nitrogen and room temperature. For the first time P_JN has been measured for total voltage drops (V_TOT) in the substrate spanning from well below to well above the value corresponding to the Si-SiO₂ barrier height (V^*_TOT=Φ_B/q=3.15 V). In contrast to MOSFET data [2], here two different injection regimes can clearly be distinguished. For V_TOT < V^*_TOT a regime occurs in which injection is no longer caused only by the electron energy gained in the electric field but also by the additional energy from phonon absorption. No lucky electron model holds true in this regime and therefore some insight will be given here by means of Monte Carlo simulations of the injection experiment. A simple analysis technique is developed, that explains the observed temperature dependence and injection regimes of P_JN.