No abstract

Heteroepitaxial growth of aluminum nitride (AIN) has been explored by experiments, but the corresponding growth mechanism is still unrevealed. Here, we use molecular dynamics simulations to study effects of temperature and N : Al flux ratio on deposited AlN. When the temperature increases from 1000 K to 2000 K with an N : Al flux ratio of 2.0, the growth rate of the AlN film decreases. The crystallinity of the deposited AlN is distinctly improved as the temperature increases from 1000 K to 1800 K and it becomes saturated between 1800 K and 2000 K. The crystallinity of the deposited film at 1800 K increases with an increase in the N : Al flux ratio from 0.8 to 2.4, and this degraded a little at an N : Al flux ratio of 2.8. In addition, stoichiometry is closely related to crystallinity of deposited films. Film with good crystallinity is connected with a near 50% N fraction. Furthermore, the average mean biaxial stress and mean normal stress at 1800 K with N : Al flux ratios of 2.0, 2.4 and 2.8 are calculated, indicating that the deposited film with lowest stress has the best crystal quality and the defects appear where stresses occur.

No abstract

No abstract

In order to study the optimal N:Al flux ratio during the deposition of AlN, the effects of N:Al flux ratio on the crystal quality (crystallinity and surface roughness) of homoepitaxial AlN are investigated. The growth temperature ranges from 1600 K to 2000 K with an increment of 200 K. When the N:Al flux ratios are changed from 0.8 to 2.8, the good crystallinity is obtained at 1600 K with the N:Al flux ratio of 2.4, while it is obtained at 1800 K with the N:Al flux ratio of 2.4 and with the N:Al flux ratio of 2.0 at 2000 K. The crystallinity at 1800 K with N:Al flux ratio of 2.4 stands out among these three. At 1800 K with varied N:Al flux ratios, the minimum surface roughness is also obtained at the N:Al flux ratio of 2.4. Further more, the distribution of deposited Al atoms at 1800 K is explored, the result shows that the uniform distribution of Al atoms appears at N:Al flux ratio of 2.4.