Growth of narrow substrate temperature window on the crystalline quality of InN epilayers on AlN/Si(1 1 1) substrates using RF-MOMBE

Abstract

Epitaxial InN films were grown on AlN/TMAl seed layer/Si(1 1 1) substrates in the range of temperature between 500 and 540 °C using pulsed-mode RF-MOMBE. The structural properties of the InN films were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy, and transmission electron microscopy (TEM). The electrical properties were characterized by Hall effect measurements. The results indicated that small changes in temperature significantly affect the quality of InN films. The XRD and TEM results indicated that the InN films grew oriented along the c-axis. Phi-scan XRD patterns indicated that the InN films grew epitaxially on the Si(1 1 1) substrates with the orientation relationship InN [1 1 −2 0]InN//[11 0]Si. When the substrate temperature at 530 °C, the TEM images indicated three-dimensional InN/AlN growth and growth rate was approximately 0.2 μm/h. The cross-sectional TEM images and SAD pattern showed a sharp InN/AlN interface and clear epitaxial orientation relationships of InN (−2 1 1 0)InN//(−2 1 1 0)AlN//(2 –2 0)Si, [0 0 0 1]InN//[0 0 0 1]AlN//[1 1 1]Si. The electron concentrations of the InN films were measured from 5.5 × 1019 to 1.3 × 1020 cm−3, and the mobility was measured from 116 to 360 cm2/V·s. The results indicate that controlling the substrate temperature is essential for engineering the growth of InN films on silicon wafers.