磁控溅射生长AlN钝化层的研究

Study on AlN Passivation Layer Grown by Magnetic Sputtering

测得AlN和Si3N4介质钝化后的AlGaN/GaN异质结的高频C-V(电容-电压)曲线,由此计算钝化层与AlGaN势垒层界面电荷面密度,发现AlN钝化层与势垒层界面的电荷面密度较Si3N4更大,同时AlN钝化层薄膜含有的可移动离子数目更多.根据I-V(电流-电压)曲线讨论了用磁控溅射技术生长的AlN钝化薄膜质量,发现AlN薄膜绝缘性不够好,可能是在室温磁控溅射生长过程中从靶材溅射出的Al原子未能与N2充分反应,导致沉积的AlN薄膜不够致密,含有的电子隧穿通道多.因此可改善反应条件以提高AlN薄膜质量.

Based on the high frequency C - V curve of the AlGaN/GaN heterostructures passivated with AlN and Si3N4 dielectric films, calculation on the charge density of the interface between the passivation layer and the AlGaN barrier layer was done in this paper. The results show that more interface charge is found in the AlN passivated barrier layer than the Si3 N4 passivated one,with the AIN film containing more removable ions. The quality of AlN passivation fihn deposited by magnetic sputtering at room temperature was discussed according to I - V curve. Compared with Si3N4 film, AIN passivation film indicates poor insulating property. The possible reason is that the incomplete reaction between the sputtering Al atoms and Natoms during the growing process resulted in the incompact structure of the deposited AlN film which contained more electron tunnel channels. Therefore, AlN passivation film is able to be improved by changing reaction conditions.