Surface recombination in bipolar transistors; accurate determination of carriers capture cross-sections of Si/SiO2 states by means of process/device simulations

The author proposes a method to determine average values of capture cross-sections relevant to accurately calculating the base current in bipolar devices. First, the trap density is measured by a DLTS (deep level transient spectroscopy) technique on MOS structures. Second, capture cross-sections are determined by means of device simulations performed on specially designed PNP transistors. An additional validation of the results is given through the simulation of a NPN structure biased in reverse mode. The accuracy level obtained on current conservation is discussed. This method proved to be more accurate than direct experimental methods