光子计数成像探测器电荷感应层Ge薄膜特性研究

Study of the Characterization of Germanium Films as the Charge Induce Layer in Photon Counting Imaging Detector

为了研究光子计数成像系统中感应电荷层Ge薄膜的制备工艺,改善光子计数成像系统的成像稳定性,采用直流磁控溅射法在熔石英衬底上制备了Ge薄膜,分析了工作气体Ar气通入量对Ge薄膜沉积速率的影响,利用表面轮廓仪及四探针表面电阻仪对样品分别进行了表面粗糙度及电学性能的表征。结果表明:随着Ar气通入量的增加,Ge薄膜沉积速率先上升后下降,在Ar气通入量为15sccm时,Ge薄膜的沉积速率出现极大值;Ge薄膜的表面粗糙度及薄膜电阻率均随着Ar气通入量的升高而增大;薄膜越厚,其电阻受氧化影响越小,电学性能越稳定。

In order to investigate the preparation process of the charge induce layer of Ge film in the photon counting imaging detector and improve the imaging stability of the photon counting imaging system, Ge films were deposited on the fused silica substrates with direct current magnetron sputtering method. The influences of the inlet argon flux on the deposition rate were analyzed. Then the surface roughness and the electric properties of the Ge films were measured by surface profiler and four-point probe surface resistance tester respectively. The results show that the deposition rate of the Ge film increases with the argon flux and achieves a maximum rate at inlet content of 15sccm, and then the deposition rate begins to decrease with further increment of the argon flux; that both the roughness and film resistivity of the Ge films increase with the argon flux; and that the thicker the film, the smaller the influence of oxidation on film resistivity and more stable of the electric property.