The Effective Ionization Rate for Hot Carriers in GaAs†

The effective hot carrier ionization rate in the field range of 2.8-3.6 × 105 v/cm has been determined in epitaxial GaAs p+-n junctions on the basis of photomultiplication measurements (on the assumption of equal hole and electron ionization rates). A fit of the ionization rate data to the theory of Baraff yields a value of λ equal to 43 Å and an ionization energy value of 1.8 ev. The ionization rate was also calculated from previously published data relating breakdown voltage to impurity concentration in step junctions and data relating breakdown voltage to impurity gradient in graded junctions. The values obtained by all three methods are in good agreement.