The effect of an electric-field gradient on avalanche noise

The effect of an electric-field gradient on the excess avalanche noise is e xamined using both a Monte Carlo model and experiment. Nonlocal effects cau se the noise to be significantly reduced as the electric-field gradient inc reases in a p(+)-n junction. For equal electron and hole ionization coeffic ients, lower noise is always achieved when carriers are injected into the h igh field end of these structures. Furthermore, for a constant noise figure and depletion thickness, a higher gain is always achieved in a p(+)-n junc tion compared a p(+)-i-n(+). The results are explained in terms of coherenc e in ionization events. (C) 1999 American Institute of Physics. [S0003-6951 (99)04145-5].