Thermionic-field emission from interface states at grain boundaries in silicon

An extension of Shockley–Read–Hall kinetics is presented for interface states at grain boundaries in silicon. The emission of majority carriers by these states is generalized to include thermionic field emission (TFE), which is shown to be important in many practical cases. Comparison is made with experimental results obtained on studies of isolated grain boundaries in silicon. One of the principal results is that energy distributions of interface states deduced from electrical characteristics of grain boundaries must be interpreted using a model which includes TFE. The importance of TFE increases with the doping concentration of the silicon N and the voltage applied across the grain boundary V and decreases with temperature. It is legitimate to neglect TFE from the interface states and consider pure thermal emission only for NV≲1016 cm−3 V at a temperature of 300 K, or NV≲1015 cm−3 V for 130 K.