CdZnTe晶体表面Au电极薄膜的制备及其欧姆接触性质

Au Film Electrodes on CdZnTe Surface:Preparation and Ohmic Contact Property

为了研究不同制备工艺对电极欧姆接触特性的影响,分别采用真空蒸发法、溅射法及化学沉积法在CdZnTe晶片表面制备了Au薄膜电极,通过测试样品的SEM、I-V曲线及交流阻抗谱,研究了不同电极制备工艺及退火处理对Au薄膜电极的微观结构及欧姆接触特性的影响。结果表明化学沉积法制备的Au薄膜表面更加平整、致密,接触势垒的高度较低,电极欧姆接触特性最好。退火处理可以改善电极的欧姆接触特性,100℃退火后,化学沉积法制备的Au电极的欧姆系数由0.883提高至0.915,势垒高度由0.492降低至0.487 e V。交流阻抗谱分析表明,化学沉积法制备电极具有最低的接触势垒,这与界面处晶片表面的掺杂及缺陷的变化有关。

Tellurium cadmium zinc（CdZnTe） is a kind of II-VI wide band-gap semiconductor compound,which is a promising material to fabricate the X-or γ-ray detectors.Its Ohmic contact property significantly influences the detector performance.In order to study the influence of preparation technology on Ohmic contact properties of the electrode,Au film electrodes were deposited by sputtering deposition,vacuum evaporation and electroless deposition.By analyzing I-V curves,SEM and AC impedance spectra,microstructure and Ohmic contact properties of the samples were studied.The results show that surtace of the sample prepared by the electroless deposition is smooth and dense showing lower contact barrier and better Ohmic contact properties smooth and Ohmic contact properties of the electrodes.After annealing at 100℃,the Ohmic coefficient of the Au electrode prepared by electroless deposition increases from 0.883 to 0.915,and the barrier height reduces from 0.492 e V to 0.487 e V,displaying improved.AC impedance spectroscopy shows that it is the change of impurity-doping and defects of CdZnTe surface at the interface that attribute to the lowest contact barrier of the Au electrode prepared by electroless deposition.