Material growth and device characterization of AlGaN/GaN single-heterostructure and AlGaN/GaN/AlGaN double-heterostructure field effect transistors on Si substrates.

An Al_0.2Ga_0.8N/GaN/Al_0.1Ga_0.9N double-heterostructure field effect transistor (DH-FET) structure was grown on a 150-mm-diameter Si substrate and the crystalline quality of the epitaxial material was found to be comparable to that of an Al_0.2Ga_0.8N/GaN single-heterostructure field effect transistor (SH-FET) structure. The fabricated DH-FET shows a lower buffer leakage current of 9.2 × 10⁻⁵ mA/mm and an improved off-state breakdown voltage of higher than 200 V, whereas the SH-FET shows a much higher buffer leakage current of 6.0 × 10⁻³ mA/mm and a lower breakdown voltage of 130 V. These significant improvements show that the Al_0.2Ga_0.8N/GaN/Al_0.1Ga_0.9N DH-FET is an effective structure for high-power electronic applications. [ABSTRACT FROM AUTHOR]