Chemical profiles of interfacial (transition) regions in InP-based heterostructures, fabricated by (1) vapor levitation epitaxy (VLE), (2) liquid phase epitaxy (LPE), and (3) molecular beam epitaxy (MBE), have been measured with a high degree of resolution on inclined surfaces by Auger electron microscopy (AES). This particular technique involves production of a chamfered wedge, characterized by a surface inclined by angle ø(≈ 0.02°) with respect to the interface, by controlled chemical etching and subsequent scanning across the trace of the interface on the (inclined) surface by AES, thereby allowing enhanced magnification of the interface by a factor of cot ø (≈ 2,000X) without deleterious effects associated with mechanical polishing and/or ion milling. Results indicate that corresponding transition widths δ between adjacent layers vary according to δLPE < δMBE < δVLE and may be explained by a combination of inherent surface roughness and interdiffusion of various chemical species across the original interface during and subsequent to the deposition process. It is concluded that the chamfered wedge technique provides a reliable and sensitive method to determine chemical profiles across a wide variety of heterojunctions, provided that a suitable chemical etch is available.