β- Ga2O3氧化物半导体单晶的生长与导电性能的研究

β-Ga2O3 is an oxide semiconductor material with wide band gap. In January 2013, Japanese researchers developed the GaN-LED devices on β-Ga2O3 substrate whose optical output power was more than five times than that of devices made on sapphire substrate at 1200mA driving current and the thermal resistance was 1/10～1/100 of that on sapphire substrate. These progresses attract extensive attentions in the world. As the substrate material for GaN epitaxy, β-Ga2O3 single crystal has the advantages of three main substrates: a combination of 0% lattice mismatch with GaN, the conductivity of SiC and light transmittance of sapphire..This project proposed that 2″ β-Ga2O3 single crystals were grown using Edge-defined film-fed growth (EFG). The temperature field, crucible and mould were self-designed using computer numerical simulation CGSim software. The conductivity of β-Ga2O3 single crystal was improved by icon doping, growth atmosphere controlling, annealing treatment, and etc. The key growth technology of 2″ β-Ga2O3 single crystal with substrate grade was strive to break through, which will promote the development of Chinese Ga2O3 based high-power white LED, UV LED , LD , β-Ga2O3 transistors and other devices.

β-Ga2O3是一种宽带隙氧化物半导体材料。2013年1月，日本科学家率先在β-Ga2O3单晶衬底上研制出的GaN基LED器件实现在大驱动电流1200mA下光输出功率达蓝宝石基板器件的5倍以上，并且热阻仅是蓝宝石基的1/10～1/100，引起国内外对β-Ga2O3的广泛关注。作为GaN衬底，β-Ga2O3单晶集三大衬底之优点：结合了与GaN晶格零失配、SiC导电性和蓝宝石透光性。.本项目提出采用EFG法生长2英寸β-Ga2O3晶体，利用计算机数值模拟CGSim软件对EFG法的温场、坩埚、模具进行自主设计；通过离子掺杂、生长气氛调控、后退火处理等途径提高β-Ga2O3单晶的导电性能。力争突破2英寸衬底级β-Ga2O3晶体生长的关键技术，推动我国Ga2O3基大功率白光LED、紫外LED、LD和β-Ga2O3晶体管等器件的发展。

β-Ga2O3晶体是一种新型第四代宽禁带半导体材料，具有物化性能稳定、机械强度高、UV透过特性、一致熔融等优点，在光电器件、功率器件、深紫外传感器等方面具有广泛的应用前景。但由于β-Ga2O3熔点高，极易分解挥发，易于解理开裂，生长大尺寸单晶十分困难。本项目通过自主设计铱金坩埚、模具及保温热场结构，有效控制了β-Ga2O3的分解挥发与开裂，发展了具有自主知识产权的导模法β-Ga2O3晶体制备技术，成功生长出2英寸β-Ga2O3单晶，晶体结晶完整，位错密度3.2×104/cm2，FWHM小于30弧秒，抛光表面粗糙度RMS＜0.2nm。同时首次通过Ge4+、In3+离子掺杂，实现了对β-Ga2O3晶体导电性能的调控，电导率提高，载流子浓度可达6×1019/cm2。项目实施期间，在核心期刊上发表、录用论文4篇，申请发明专利3项，其中授权1项。