基于蒙特卡罗方法的GaN,SiC等半导体β辐射特性研究

Numerical Simulation of β Radiation-ionizing Characteristics of GaN, SiC et Semiconductor Materials Using Monte Carlo Method

利用蒙特卡罗方法研究了GaN、SiC等几种宽带隙半导体材料在β源辐照下的行为。结果表明表层中沉积的β粒子数密度随材料密度的增加而增加,其最大电子数密度与物质密度间存在近似的线性关系;电子数密度随粒子入射深度成指数衰减,随横向迁移距离的增加而迅速衰减,其横向最大迁移距离在6 mm左右。相对高能电子而言,低能电子更容易发生电离作用,且电子的沉积能随入射深度逐渐减少。对于0.1500 keV的入射电子,GaN、SiC等半导体材料的背散射系数大约在0.040.38之间,其大小与材料及入射电子能量有关。β粒子在GaN、SiC等材料中的射程都比较短,对于0.5 MeV的β粒子其最大射程不超过1 mm。

Radiation - ionizing characteristics of GaN, SiC and other typical wide band - gap semiconductor materials irradiated by the β isotopic source were simulated using Monte Carlo method. The electron density of Material surface increased with the semiconductor density. A approximate linear relationship exist between the maximum electron density and the material density. The electron density is decreased exponentially with penetration depth and rapid attenuated with increasing the lateral migration distance. Its maximum migration length is about 6 ram. Low energy electron is ionized more likely than the high - energy electron. The deposited energy reduces gradually with the depth of the incident electron. The electronic backscatter coefficient of GaN, SiC and similar semiconductor material is about 0.04 - 0.38 for 0.1 - 500 keV incoming particle energy. Its value depends on the type of materials and incident electron energy. The Range of electron is short in those semiconduc- tor materials and its maximum value is no more than 1 mm for 0.5 MeV beta particles.