Growth of Large GaN Single Crystals on High-Quality GaN Seed by Carbon-Added Na Flux Method

Seeded growth on high-quality GaN seed was studied using a carbon-added Na flux method. A GaN single crystal (8.6 mm long, 5 mm high) was grown in 96 h without polycrystal formation on a crucible. Under a carbon-added condition, dependence of the growth rate of the seed and the growth habit on the flux composition was studied. We found that the growth rate was higher with Ga-poor flux, resulting in a high growth rate of 30 µm/h along the c-axis and 33 µm/h along the a-axis (66 µm/h for both sides). The growth habit changed from prismatic to pyramidal with increasing Ga composition.

采用添加碳的钠助熔剂法研究了在高质量氮化镓籽晶上的生长情况。在96小时内，在坩埚上生长出了一个长8.6毫米、高5毫米的氮化镓单晶，且无多晶形成。在添加碳的条件下，研究了籽晶生长速率和生长习性对助熔剂成分的依赖性。我们发现，贫镓助熔剂的生长速率更高，导致沿c轴的生长速率高达30微米/小时，沿a轴的生长速率为33微米/小时（两侧总计66微米/小时）。随着镓成分的增加，生长习性从棱柱形变为金字塔形。