Technology development for the growth of semi-insulating bulk GaN and investigation of in-situ carbon doping

氮化半导体的研究是当前先进电子学和光电子学领域最具挑战性的课题之一。提出的研究计划的动机是目前缺乏用于所有氮基电子器件的高质量和廉价的半绝缘（SI） GaN衬底。它将专注于开发一种基于伪卤化物气相输运（PVPE）的新型GaN技术，与掺铁hvpe生长材料相比，该技术将显著改善SI体晶体的结构完善。“伪卤化物”代表了Ga的碳基输运和随后与氨的反应生成GaN，利用自组织碳掩膜在生长的初始阶段降低位错密度，同时在随后的GaN体生长中保持碳含量低于溶解度限制。通过在不含石墨材料的生长室中引入含碳气体来控制碳的掺入。高结晶完美的生长体GaN将被碳掺杂，从而提供SI性能。将探索和控制体GaN的电学特性。由碳掺杂引起的补偿机制的基础研究将通过应用最先进的表征方法进行。

Nitride semiconductor research is presently one of the most challenging topics in the field of advanced electronics and optoelectronics. The proposed research program is motivated by the present lack of high-quality and inexpensive semi-insulating (SI) GaN substrates for all nitride-based electronic devices. It will focus on developing a novel GaN technology based on pseudohalide vapour phase transport (PVPE) for a significant improvement of the structural perfection of SI bulk crystals in comparison to Fe-doped HVPE-grown material. The 'pseudohalide' stands for a carbon-based transport of Ga and a subsequent reaction with ammonia to form GaN, utilizing a self-organized carbon mask to reduce the dislocation density at initial stages of growth, while keeping the carbon content below the solubility limit in subsequent GaN bulk growth. Control of carbon incorporation is provided by introduction of carbon-containing gas in a growth chamber free from graphite materials. The grown bulk GaN of high crystalline perfection will be carbon-doped which provides for SI properties. The electrical properties of the bulk GaN will be explored and controlled. Fundamental studies of the compensation mechanisms arising from carbon doping will be performed by applying state-of-the-art characterization methods.