Abstract

Scanning spreading resistance microscopy (SSRM) ² based on atomic force microscopy (AFM) and employing a conductive tip in direct contact with the sample surface allows semiquantitative measurement of the spatial distribution of charge carriers in an optoelectronic device. The distribution of dopants in the active and current-blocking regions of the buried-heterostruc-ture (BH) multiple-quantum-well (MQW) lasers plays a key role in determining device performance. We report herein the results of calibrated high-spatial-resolution SSRM measurement, showing that we are able to resolve individual quantum wells and determine the activated doping of the p-n-p-n thyristor current blocking layers of a BH MQW laser. Our results demonstrate the utility of calibrated SSRM to delineate quantitatively the transverse cross-sectional structure of complex two-dimensional devices such as MQW BH lasers, in which traditional one-dimensional probing using secondary ion mass spectroscopy (SIMS) provides only a partial picture of internal device structure.

© 2002 Optical Society of America