Suppressing Carbon Incorporation in Metal–Organic Chemical Vapor Deposition GaN Using High‐Offcut‐Angled Substrates

Abstract

Carbon (C) is a common impurity that acts as a compensator within GaN grown via metal–organic chemical vapor deposition (MOCVD). Reducing C in GaN will help reduce the compensation level and provide a route to achieve GaN with reliably low effective doping for high‐power device applications. GaN grown with fast growth rates on bulk GaN with various offcut angles via conventional‐MOCVD (C‐MOCVD) and laser‐assisted MOCVD (LA‐MOCVD) is compared and analyzed. C‐incorporation effects are compared through quantitative secondary‐ion mass spectroscopy analysis in GaN grown on GaN substrate with offcut angles of 4° and 0.3° toward m‐plane over a wide range of growth rates by C‐MOCVD and LA‐MOCVD. For both growth techniques investigated, a significant reduction in C‐incorporation is observed when a high‐offcut‐angle (4°) substrate is used as compared to a lower‐offcut‐angle (0.3°) substrate. With C‐MOCVD, at the fastest growth condition investigated (17.26 μm h−1 at 0.3°‐offcut, 15.25 μm h−1 at 4°‐offcut), a reduction in [C] by 21.2X is observed with an increase in the offcut angle from 0.3° to 4°. A 82.6X reduction in [C] is observed with the similar fast growth condition via LA‐MOCVD on GaN with 4° offcut angle (9.78 μm h−1) as compared to C‐MOCVD at 0.3° offcut angle (17.26 μm h−1).