Hot-Wall MOCVD for Highly Efficient and Uniform Growth of AIN

We demonstrated successful growth of AIN at a temperature of 1200 degrees C in a set of hot-wall MOCVD systems with the possibility of straightforward scaling up the process on larger wafer areas to meet the demand of device technologies. We outlined several aspects of the carefully optimized design and process parameters with relevance to achievement of a high overall growth rate (1 and up to 2 mu m/h), efficiency, and uniformity, which to a great extent depends on how consumption of growth-limiting species by gas-phase adduct formation can actively be prevented. Mixing of the precursors upstream from the deposition area facilitates uniform epitaxial growth, while the greater uniformity of substrate temperature inherent to the hot-wall reactor and rotation of the wafer are of fundamental importance for layer-growth uniformity. The AIN layer thickness can be controlled with an accuracy of +/- 1.3% on 2 in. wafers. The low-temperature cathodoluminescence spectrum of the AIN epitaxial material is strongly dominated by the intense near band-gap deep UV emission at about 208 nm.