RELATING COMPUTER-SIMULATION STUDIES WITH INTERFACE STATE MEASUREMENTS ON MIS SOLAR-CELLS

A lock-in-amplifier technique has been used to measure interface state density (Nss) values ranging from 2 ×1011−3 × 1013 states/cm2. eV depending on energy in the gap, type of Si substrate, and choice of Schottky metal used in MIS diodes. Polycrystalline, ribbon, and (100) single-crystal Si substrates with 40–60-Å interfacial oxides have been tested using Cr, Al, Ti, and Cu as Schottky metal. A computer simulation is used to predict the influence of interface states, interfacial oxide thickness (δ), and Schottky metal on open-circuit voltage (Voc). A reduced Voc and fill factor are shown for δ> 15 Å. A reduced Voc occurs when Nss> 1012 states/cm2. eV and capture cross section (σ) > 10−15 cm2. The influence of Schottky metal on Voc is also clearly seen. Very close agreement is shown between experimental and theoretical values of Voc as δ, Nss, and metal type are selected. This study clearly relates experimental and theoretical data to permit design of more efficient MIS solar cells. Copyright © 1979 by The Institute of Electrical and Electronics Engineers, Inc.