基于氧化鎵薄膜的高性能日盲紫外探测材料和器件的设计及制备研究

Ga2O3 thin films of various crystal phases would be grown on Al2O3 or GaN substrates with different crystal faces by laser molcular beam epitaxy (LMBE) technique. The orientation of crystal plane may be adjusted by optimizing the growth conditions. A large gain can be obtained in the solar blind ultraviolet region, and the technique of highly sensitive spectral response will be realized. Sn(Si)-doped Ga2O3 thin films are prepared by LMBE. n-Ga2O3 thin films with low resistance and good stability will be realized by surface passivation, plasma treatment and rapid annealing. By taking into account energy band engineering and interface engineering, n-Ga2O3/p-GaN heterojunctions are designed and prepared. Preparation technology and micro machining technology of ohmic contact electrode and Schottky contact electrode are studied. A high performance n-Ga2O3/p-GaN heterojunction solar blind UV detector will be achieved. On this basis, a new solar-blind ultraviolet photo transistor will be designed and prepared, which can further reduce the dark current, and improve the UV / visible rejection ratio and the signal / noise ratio. This work can provide an experimental approach to realize the detector with strong detection ability, which can detect weak solar-blind UV light in strong visible light and high-noise background. The project will has very important significance to fabricate and develop solar-blind UV detection technology with the practical application value.

利用激光分子束外延技术，选择不同晶面的蓝宝石、氮化镓衬底制备各种晶相结构的Ga2O3薄膜，并通过优化生长工艺调控晶面取向，在日盲紫外波段获得较大的增益，实现高灵敏的光谱响应特性技术；制备Sn(Si)掺杂的Ga2O3薄膜，通过表面钝化、等离子体处理和快速退火等工艺，实现低阻、稳定的n-Ga2O3薄膜；通过能带工程、界面工程设计制备n-Ga2O3/p-GaN异质结，研究欧姆接触和肖特基接触的电极制备技术和电极微加工技术，实现高性能的n-Ga2O3/p-GaN异质结日盲紫外探测器。在此基础上，设计制备新型的n-Ga2O3/p-GaN异质结日盲紫外光电晶体管，进一步降低器件的暗电流，提高紫外/可见抑制比和信号/噪声比，为实现在强可见光和高噪声背景下对较弱日盲紫外光探测能力较强的探测器件提供实验途径，本项目对于研制和发展具有应用价值的日盲紫外光探测器具有重大意义。

作为一种直接带隙的二元宽禁带氧化物半导体材料，Ga2O3是一种前景广阔的蓝光和紫外材料，非常适合制作短波段发光器件和紫外光探测器件。本项目针对目前Ga2O3薄膜在日盲紫外探测器研究中存在的材料问题，提出了开展用于微弱信号探测的高性能日盲紫外探测材料的制备研究。利用对生长工艺及材料结构的调制，实现载流子浓度、光响应度、光暗电流比等光电性能的显著提升，确保了Ga2O3基薄膜日盲紫外探测器件在日盲紫外波段的高灵敏度及快速响应等性能提升。.利用激光脉冲沉积、聚合物辅助沉积和磁控溅射等技术，开展了Ga2O3薄膜材料的制备研究，并通过生长动力学、晶体形貌、结晶完整性等方面的研究，探讨生长机理；通过对薄膜的制备工艺、生长条件等的实验探究，得到了单晶结构、非晶结构、多晶结构、混相结构及纳米棒状结构的Ga2O3薄膜。对基于不同结构的Ga2O3薄膜制备的日盲紫外探测器及薄膜晶体管器件，通过能带工程、界面工程设计及制备等工艺优化及结构调控可以大幅提升器件各项光电器件性能指标，其中光响应度最高可达2.6×105A/W，光暗电流比可达到1.6×108。实施了掺杂调制及器件结构优化等方案进一步提高Ga2O3基薄膜材料的光电探测性能。通过对Ga2O3的结构分析，确定了掺杂调控过程中的稳定性及带边调控机制，并通过阳离子掺杂、阴离子掺杂及阴阳离子np共掺杂等高通量筛选确定了Ga2O3掺In、S、Al-S、N-Ge等掺杂体系的可行性分析，实现了材料的紫外区全谱探测，为掺杂调控Ga2O3基高性能日盲紫外探测器提供理论基础及可行性备选材料筛选。基于上述研究基础及可行性研判，对Ga2O3薄膜材料进行掺杂调制，并通过工艺优化及MSM、异质结等器件结构设计制备了掺杂的Ga2O3基薄膜晶体管器件，得到了光电性能及探测性能的进一步提升。为最终实现具有实际应用价值的日盲紫外光阵列探测器件提供技术服务。.综上所述，通过工艺优化及结构调制，我们成功实现了Ga2O3基薄膜材料在日盲紫外探测领域的性能提升，为未来高性能、低成本的高性能日盲紫外探测器件的生产和应用提供了积极推动作用。