Measurement of isotype heterojunction barriers by C-V profiling

Abstract

The Debye length smearing that occurs in C‐V profiling has precluded the use of C‐V profiling from an adjacent Schottky barrier to measure the magnitude of energy band discontinuities at barriers in isotype heterojunctions. It is observed, however, that in such a process both the number of the charge carriers and the moment of their distribution are conserved. This information permits the extraction of values for both the conduction band discontinuity ΔE_c and any interface charge density. This technique and experimental results for an LPE‐grown n‐N GaAs‐Al_0.3Ga_0.7As heterojunction are described. We find ΔE_c =0.248 eV, corresponding to about to 0.66ΔE_g rather than Dingle’s commonly accepted value 0.85ΔE_g . The difference is attributed to compositional grading during LPE growth.