Non Local Electron and Hole Impact Ionization in Advanced Si BJTs

This report describes a modeling and experimental study of electron and hole impact ionization in silicon bipolar transistors. A method is developed to extract simultaneously the effective field (carrier temperature) dependent electron and hole ionization coefficients from multiplication coefficient data. A simple non local impact ionization model for electrons and holes is developed and the model parameters are extracted by means of comparison with accurate Monte Carlo calculations. The model is used to predict the breakdown voltage of Zener diodes as well as collector-base and collector emitter breakdown voltages of a variety of silicon BJT's fabricated with the SUBILO and DOUBLE POLY processes. The operational validity limits of the model are also assessed by means of calculations on template rectangular and triangular field profiles of varying depletion-region-extension and peak-electricfield -value. The activities were carried out as part of Philips Nat. Labs. cooperation with DIEGM, University of Udine, Italy. Conclusions: In summary, our analysis of electron and hole impact ionization in advanced bipolar devices and Zener diodes concentrated on the following subjects: # Koninklijke Philips Electronics N.V. 2000 iii .