氮化镓基薄膜材料的测试和评价

The Evaluation and Measurement of GaN-based Film Material

氮化镓基薄膜材料由于外延衬底与氮化镓基薄膜材料之间存在较大的晶格失配,因此氮化镓基薄膜材料,特别是铝镓氮薄膜材料的质量还需要有很大的提高。本文利用紫外可见透射光谱,电流电压特性曲线测试,以及二维透射扫描系统来评价氮化镓基薄膜材料。利用紫外可见透射光谱,可以得到材料的截止波长、吸收边以及在可见光波段的透射率,从而对材料的组分以及材料的异质结界面作出评价;利用简单的电流电压特性曲线测试可以对薄膜材料最表层的电导能力有所了解;而利用搭建的二维透射扫描系统则可以对材料均匀性进行量化的评价。通过以上这些非损伤性的测试评价手段,对氮化镓基薄膜材料的光学、电学以及均匀性等各方面的重要性能作出定性和半定量的评价,从而对薄膜材料生长以及后续的大面阵芯片制作提供极其重要的指导。

Due to large lattice mismatch between sapphire substrate and heterostructure epitaxial material, quality of GaN-based material, especially with a high Al mole fraction, need＇to be improved in a long period. In the paper, transmission spectrum in the UV and visible spectral range, current-voltage measurement and a two dimension transmission scanning system （2-DTSS） are employed to evaluate the properties of GaN-based material. The bandgap, absorption edge and transmission in visible spectral range obtained from the measurement of transmission spectrum can be used to evaluate the mole fraction of epitaxial material and hetero-epitaxial interface, respectively. Current-voltage measurements and 2-DTSS are employed to show uniformity of GaN-based material. By above undamaged measurements, the optical, electrical and uniformity properties are qualitatively or quantificationally evaluated.