Dual-Site Collaborative Growth of High-Quality AlN Single Crystals for High-Performance HEMT Devices

Abstract

Aluminum nitride, as a key third-generation semiconductor material, faces limitations in single-crystal growth due to the scarcity of high-quality AlN seed crystals and quality degradation during the iteration process. This study proposes a dual-seed growth method, simultaneously placing seeds at the crucible top and the AlN source surface. Experiments demonstrate that crystals grown on the source surface (Seed 2) exhibit superior quality, making them the optimum high-quality seeds. Concurrently, the crystal growing from the crucible top (seed 1) achieved a higher growth rate with controllable quality. Based on these findings, a “dual-point synergistic growth” strategy was proposed: first, a high-quality crystal was grown on Seed 2 as a seed crystal, which was then transferred to Seed 1 for rapid expansion. Crystals grown by this method were used to fabricate and characterize HEMT devices. Results demonstrate that AlN-based devices exhibit low contact resistance, excellent ohmic contact quality, and stable channel resistance characteristics. This approach significantly enhances growth efficiency while maintaining high crystal quality, providing a viable pathway for large-scale AlN manufacturing.