Device parameters extraction in separate absorption, grading, charge, and multiplication InP/InGaAs avalanche photodiodes

In this paper, we report a simple, innovative, fast, accurate, and nondestructive technique for extracting two critical device parameters-multiplication layer thickness x/sub d/ and integrated areal charge density /spl sigma//sub active/ in separate absorption, grading, charge, and multiplication (SAGCM) InP/InGaAs avalanche photodiodes (APDs), using punchthrough and breakdown voltages obtained from dc photocurrent measurements, We consider in detail the systematic uncertainties due both to the neglect of ionization in the absorption and charge layers, and to different ionization rates in InP reported in the literature. We also consider random errors caused by uncertainties from experiments and other device parameters, The combined error for x/sub d/ is <0.05 /spl mu/m, and for /spl sigma//sub active/ is <3%, and these errors are smaller than errors associated with x/sub d/ and /spl sigma//sub active/ determined using current techniques of secondary ion mass spectroscopy (SIMS) and Hall analysis, which are destructive and/or require separate calibration wafers.