Soft-threshold lucky drift theory of impact ionisation in semiconductors

Arguments are presented for the existence of a soft threshold to impact ionisation in GaAs and other related semiconductors. A soft-threshold factor is introduced into the theory of lucky drift and the results are applied to some major semiconductors. Excellent fit of theory to experiment is obtained, which confirms that the thresholds are indeed soft. Soft-threshold factors and new mean free paths are obtained for Ge, Si, GaAs, InP and GaP. The mean free paths are shown to obey a simple law. The results for GaAs are applied to the case of multilayer APD. It is shown that excellent agreement with the results of Capasso et al. (1982) are obtained, even with a 60:40 division of band edge discontinuity.

[1]  B. Ridley A model for impact ionisation in wide-gap semiconductors , 1983 .

[2]  Karl Hess,et al.  Band-structure-dependent transport and impact ionization in GaAs , 1981 .

[3]  A. Choudhury,et al.  Ionization coefficients measured in abrupt InP junctions , 1980 .

[4]  B. Ridley Lucky-drift mechanism for impact ionisation in semiconductors , 1983 .

[5]  K. Brennan,et al.  Experimental determination of impact ionization coefficients in , 1983, IEEE Electron Device Letters.

[6]  R. Abram,et al.  Overlap integrals for Auger recombination in direct-bandgap semiconductors: calculations for conduction and heavy-hole bands in GaAs and InP , 1984 .

[7]  Federico Capasso,et al.  Enhancement of electron impact ionization in a superlattice: A new avalanche photodiode with a large ionization rate ratio , 1982 .

[8]  G. E. Stillman,et al.  Electron and hole impact ionization coefficients in InP determined by photomultiplication measurements , 1982 .

[9]  R. Abram,et al.  Calculations of the commonly neglected terms in the matrix element for Auger and impact ionisation processes in semiconductors , 1984 .

[10]  K. Hess,et al.  Impact ionization of electrons in silicon (steady state) , 1983 .

[11]  E. Kane Electron Scattering by Pair Production in Silicon , 1967 .

[12]  C. R. Crowell,et al.  Impact ionization by electrons and holes in InP , 1980 .

[13]  D. Robbins Aspects of the Theory of Impact Ionization in Semiconductors (I) , 1980 .

[14]  M. Burt,et al.  Overlap integrals for Auger recombination in direct gap III-V semiconductors: calculations for conduction and heavy hole band states with wavevectors along the (001) direction in GaAs and InP , 1984 .

[15]  C. R. Crowell,et al.  Effective threshold energy for pair production in nonpolar semiconductors , 1976 .

[16]  M. Burt An alternative expression for the impact ionisation coefficient in a semiconductor derived using lucky drift theory , 1985 .

[17]  G. A. Baraff,et al.  Distribution Functions and Ionization Rates for Hot Electrons in Semiconductors , 1962 .

[18]  R. A. Logan,et al.  Ionization Rates of Holes and Electrons in Silicon , 1964 .

[19]  Karl Hess,et al.  Theory of hot electron emission from silicon into silicon dioxide , 1983 .