Based on the two-step growth, GaN and AlGaN on sapphire (0 0 0 1) were grown by MBE using an RF-source. We have attained a very flat growing surface by optimizing growth conditions both for the buffer layer and the main growth. We also grew AlGaN/GaN superlattices to demonstrate the flatness achieved on the growth surface. From X-ray diffraction and transmission electron microscopy observations, the abruptness of the interfaces and excellent controllability of the thickness were confirmed.
- Transmission electron microscopy
- X-ray diffraction