Investigating the growth of AlGaN/AlN heterostructure by modulating the substrate temperature of AlN buffer layer

摘要

We have investigated the impact of AlN buffer layer growth parameters for developing highly single crystalline AlGaNfilms. The low mobility of Al adatoms and high temperature for compound formation are amongst the major causes thataffects the growth quality of AlGaN films. Thus, proper optimization need to be carried out for achieving high qualityAlGaN due to an augmented tendency of defect generation compared to GaN films. Thus, growth conditions need to beamended to maximize the incorporation ability of adatoms and minimize defect density. So, this study elaborates thegrowth optimization of AlGaN/AlN/Si (111) heterostructure with varied AlN buffer growth temperature (760 to 800 °C).It was observed that the remnant Al in low temperature growth of AlN buffer layer resist the growth quality of AlGaNepitaxial films. A highly single crystalline AlGaN film with comparatively lowest rocking curve FWHM value (～ 0.61°) andsmooth surface morphology with least surface defect states was witnessed when AlN buffer was grown at 780 °C. Fromthe Vegard’s law, the photoluminescence analysis unveils Aluminium composition of 31.5% with significantly reduceddefect band/NBE band ratio to 0.3. The study demonstrates good crystalline quality AlGaN film growth with Aluminiumcontent variation between ～ 30–39% in AlGaN/AlN heterostructure on Si(111) substrate leading to a bandgap rangewhich is suitable for next-generation solar-blind photodetection applications.