Development of a 2-inch GaN wafer by using the oxide vapor phase epitaxy method

From the previous studies, one of the challenges in the oxide vapor phase epitaxy (OVPE) method was suppressing poly-crystal generation for thick GaN growth. In this study, thick GaN growth was realized by controlling the supersaturation ratio using thermodynamic analysis, and an OVPE-GaN wafer of 300 μm-thick was obtained. As a result of evaluating the quality of the OVPE-GaN wafer, it was confirmed that both the high oxygen concentration and the high crystallinity were achieved. The resistivity was 7.75 × 10−4 Ω cm and the threading dislocation density (TDD) was 8.8 × 104 cm−2. It was newly found that the OVPE method can reduce TDD from the order of 106 cm−2 to the order of 104 cm−2 with a grown thickness of less than 500 μm. From these results, it was proved that the OVPE method has a great potential of manufacturing low resistivity and low TDD GaN wafers.