SURFACE RECOMBINATION, FREE-CARRIER SATURATION, AND DANGLING BONDS IN INP AND GAAS

Surface recombination and free-carrier saturation both influence the performance and scaling of bipolar semiconductor devices. These two apparently unrelated material properties have a common origin in the band structure of the semiconductor. Although InP and GaAs have similar bandgaps as well as similar effective masses and dielectric constants, InP has dramatically different surface recombination velocities and free-carrier saturation limits than GaAs. These differences can be explained by a single comparison of the average dangling bond energy in the two materials. The dangling bond energy determines the location of the maximum density of surface states in the bandgap and controls the formation of native amphoteric defects which compensate shallow dopants. Semiquantitative predictions based on this principle are presented for InGaAsP/InP. © 1990.