13N超高纯锗单晶的制备与性能研究

Preparation and Properties of 13N Ultra-High Purity Germanium Single Crystals

13N超高纯锗单晶是制作超高纯锗探测器的核心材料。本文通过还原法获得还原锗锭,再由水平区熔法提纯获得12N高纯锗多晶,最后由直拉法生长得到13N超高纯锗单晶。通过低温霍尔测试、位错密度检测、深能级瞬态谱(DLTS)测试对13N超高纯锗单晶性能进行分析。低温霍尔测试结果显示,晶体头部截面平均迁移率为4.515×10^(4)cm^(2)·V^(-1)·s^(-1),载流子浓度为1.176×10^(10)cm^(-3),导电类型为p型,位错密度为2256 cm^(-2);尾部截面平均迁移率为4.620×10^(4)cm^(2)·V^(-1)·s^(-1),载流子浓度为1.007×10^(10)cm^(-3),导电类型为p型,位错密度为2589 cm^(-2)。晶体深能级杂质浓度为1.843×10^(9)cm^(-3)。以上结果表明该晶体是13N超高纯锗单晶。

13N ultra-high purity germanium single crystal is the core material for producing ultra-high purity germanium detectors.This article obtains reduced germanium ingots by reduction method,then purifies them by horizontal zone refining method to obtain 12N high-purity germanium polycrystals,and finally grows 13N ultra-high purity germanium single crystals by Czochralski method.The performance of 13N ultra-high purity germanium single crystal was tested and studied through lowtemperature Hall test,dislocation density test,and deep level transient spectroscopy(DLTS)detection.The low-temperature Hall results show that the average mobility of the crystal head cross-section is 4.515×10^(4)cm^(2)·V^(-1)·s^(-1),the carrier concentration is 1.176×10^(10)cm^(-3),and the conductivity is p-type,the dislocation density at the crystal head is 2256 cm^(-2).The average mobility of the tail section is 4.620×10^(4)cm^(2)·V^(-1)·s^(-1),the carrier concentration is 1.007×10^(10)cm^(-3),and the conductivity type is p-type,the dislocation density at the tail of the crystal is 2589 cm^(-2).The concentration of deep level impurities in the crystal is 1.843×10^(9)cm^(-3).The results indicate that the crystal is 13N ultra-high purity germanium single crystal.