Strain-induced step bunching in orientation-controlled GaN on Si

Abstract

We report a technique for the fabrication of high-quality GaN-on-silicon (Si) substrates for use in various power applications. GaN epitaxial layers were generated on Si(111) vicinal faces that had been previously covered with a thin coating of Al2O3 to control the orientation of the AlN seed layers. We obtained orientation-controlled GaN layers and found a linear relationship between the GaN c-axis and Si[111] tilt angles. As a result, the threading dislocation density in the AlN seed layer was reduced and high-quality GaN layers were generated. The X-ray rocking curves for these layers exhibited full width at half maximum values of 390′′ and 550′′ for the (004) and (114) reflections, respectively. Significant step bunching was observed on a GaN(0001) vicinal face produced using this technique, attributed to strain-induced attractive interactions between steps. Thus, by controlling the strain near the surface layer, we achieved the step flow growth of GaN on Si.

Полуполярные Широкозонные III-N-слои На Кремниевой Подложке: Эпитаксия С Контролем Свойств Структур (Обзор)

“…Сообщается о квантово-размерных устройствах InGaN/GaN на платформе GaN-on-Si, которые обладают разными функциональными возможностями [55][56][57][58][59][60][61]. Эпитаксия с контролем ориентации слоев GaN на подложке Si (111) была продемонстрирована на примере очень тонкого слоя Al 2 O 3 , который контролировал ориентацию затравочных слоев AlN [62]. Анизотропная модель для напряжений, вызванных термическим несоответствием между пленкой и подложкой, в пленках нитрида галлия и нитрида алюминия, выращенных на подложках Si (111), опубликована в [63].…”

Nanometer-thin ALD-Al2O3for the improvement of the structural quality of AlN grown on sapphire substrate by MOVPE

“…This method was also employed for polarity control of GaN . Moreover, several nanometer‐thick ALD‐Al 2 O 3 was deposited on (111)Si vicinal face for orientation control of (001)GaN as well as for strain‐induced step bunching . Recently, ALD was used to precisely control the conformal Al 2 O 3 thin film with atomic spatial resolution, providing the chance to study the effect of highly uniform dielectric shells on different surface plasmon resonance (SPR) modes .…”