AlGaN/GaN异质结材料的中子辐照效应

Neutron Radiation Effects of AlGaN/GaN Heterostructures Materials

采用归一化能量1 Me V的中子脉冲反应堆对Al Ga N/Ga N异质结材料进行了辐照研究。实验发现,经1015cm-2注量的中子辐照后,异质结材料的二维电子气(2DEG)载流子浓度(ns)下降,而2DEG迁移率由于受到ns的调制作用略有增加,同时辐照导致的载流子浓度ns下降造成了沟道串联电阻的增加和异质结构阈值电压(VTH)的正向漂移。分析认为,辐照感生类受主缺陷是造成ns下降和阈值电压漂移的原因。原子力显微镜(AFM)和X射线衍射仪(XRD)的测试结果表明,辐照后材料的表面形貌有所恶化,材料应变基本不变,而材料的螺位错和刃位错密度辐照后都略有增加。此外,实验结果还表明初始材料质量越好,辐照退化越小。

The radiation effects of Al Ga N / Ga N heterostructures were investigated by using 1 Me V neutron radiation source. The experiment shows that after the neutron radiation with the fluences of 1015cm- 2,the carriers concentration（ ns） of two-dimensional electron gas（ 2DEG） decreases and the mobility of 2DEG increases slightly because of the carrier concentration modulation. As the decreased ns caused by radiation, the threshold voltage（ VTH） positive shifted, the channel series resistance increased. The decreased nsor the shifted VTHare attributed to radiation induced acceptor defects in heterostructures. The atomic force microscopy（ AFM） and X-ray diffraction（ XRD） indicate that after the radiation, the surface morphology of the material is deteriorated and the strain is basically unchanged,while the screw dislocations and the edge dislocations density increase slightly. In addition,the test results show that the better initial material quality, the less radiation degradation would be shown.