中子辐照掺氮6H-SiC晶体的电学性能及退火的影响  

Electrical Properties and Annealing Behavior of Nitrogen Doped 6H-SiC Crystals Irradiated by Heavy Neutron

作　　者：陈敬[1] 阮永丰[1] 李连刚[1] 祝威[2] 王鹏飞[1] 侯贝贝[1] 王帅[1] 

机构地区：[1]天津大学理学院,天津300072 [2]天津商业大学理学院,天津300134

出　　处：《硅酸盐学报》2013年第6期812-819,共8页Journal of The Chinese Ceramic Society

摘　　要：在60～80℃用剂量为1.67×1020n/cm2的全能谱中子对掺氮6H-SiC晶体进行了辐照,对辐照样品从室温至1600℃进行了等时退火,研究了辐照和退火对样品电学性能的影响。大剂量中子辐照在晶体内产生了大量缺陷和损伤,并引起样品的电学性能发生变化,使电阻率升高、介电常数和介电损耗减小。测试表明:在辐照缺陷及其电学性能的退火演化过程中,存在约为1000和1400℃两个特征温度。当退火温度低于1000℃时,随着退火温度的升高,电阻率小幅增加,而介电常数和介电损耗亦下降;在退火温度高于1 000℃时,电阻率开始下降。在退火温度高于1 400℃时,电阻率急剧地下降,而介电常数和介电损耗快速地增加。以间隙原子和空位为缺陷的主要形式作为辐照损伤的模型,对上述现象做了定性解释。测试还表明,掺氮6H-SiC的介电常数高达3.5×104,这一奇特的物性主要来源于电子的长程迁移极化。Nitrogen doped 6H-SiC single crystals were irradiated by whole spectral neutrons with a fluence of 1.67× 10^20 n/cm2 at 60-80 ℃. The specimens were isochronally annealed from room temperature to 1 600 ℃. The influences of irradiation and annealing on the electrical properties of the sample were investigated. The massive defects and damages in the sample are induced by the irra- diation, resulting in the enormous increase of the resistivity and the decreases of dielectric constant and dielectric loss. The results show that there are two characteristic temperatures in the evolution process of defects and electric properties on the annealing, i.e., 1 000 ℃ and 1 400 ℃, respectively. At the annealing temperature of 〈 1 000 ℃, the resistivity of irradiated sample slightly increases, while the dielectric constant and the dielectric loss decrease with the increase of annealing temperature. At the annealing temperature of 〉 1 000 ℃, the resistivity decreases. The resistivity decreases, but the dielectric constant and the dielectric loss increase at the an- nealing temperature of 〉 1 400 ℃. These phenomena could be explained through an irradiation damage model based on that the inter- stitial atoms and vacancies are dominating defects in the irradiated crystal. Also, the dielectric constant of nitrogen doped 6H-SiC is 3.5 × 10^4. This peculiar property is mainly formed due to the electronic long range migration polarization.

关 键 词：掺氮碳化硅晶体 中子辐照 退火 电阻率 介电性能 

分 类 号：O774[理学—晶体学]