IMPACT IONIZATION IN THIN ALXGA1-XAS (X=0.15 AND 0.30) P-I-N-DIODES

The electron and hole multiplication characteristics, M-e and M-h, res pectively, have been measured in two series of AlxGa1-xAs (x= 0.15 and 0.30) p-i-n diodes where the i-region thicknesses, w, vary from 1.0 d own to 0.025 mu m. From these, the effective electron and hole ionizat ion coefficients, alpha and beta, respectively, have been determined a nd in the thicker structures agreement is found with data published pr eviously in the literature. However, in the devices where w less than or equal to 0.1 mu m, the dead space effect reduces multiplication bel ow their bulk values at lower values of bias. As the bias is increased , alpha and beta increase very rapidly suggesting that overshoot effec ts are compensating for the dead space. (C) 1997 American Institute of Physics.