用电火花技术制作P型高阻硅的欧姆接触

检测高阳硅单晶材料的杂质补偿度和迁移率时,必须要有良好的欧姆接触。本文提出用银头烙铁将多元合金(InBAlNi)涂敷在P型硅片上,经电火花放电技术可对电阻率高达1000Ωcm的样品制成欧姆接触。通过电流电压特性、接触电阻率和离子探针的测量,讨论了欧姆接触的机理和载流子输运的特征。电火花技术使多元合金与高阻P型硅样品在电容器放电的瞬间所产生的高能量作用下,交界面处的硅与合金相互熔融,冷却时,电活性受主元素又以高浓度析出,使原来的高阻硅变为P~ ,形成了欧姆接触。不同温度的接触电阻率测量,结合与掺杂浓度关系的计算表明,穿过金属与半导体硅接触的电流输运是热离子场发射机理,载流子隧穿势垒是主要的输运过程。

OHMIC CONTACT ON THE HIGH RESISTIVITY P-TYPE SILICON EFFECTED BY THE TECHTIQUE OF ELECTRICAL SPARKING

Good quality ohmic contact is necessary in the measurements of impurity compensation and mobility on high resistivity silicon single crystal materils. In this paper we propose a two-step process where by good ohmic contact is produced when the silicon resistivity is as high as 1000Qcm, The first step is to smear the multi-component-alloy (I BAlNi) on the p-type silicm wafer by using a silver head electric soldering iron and thon employ the technique of electrical spark discharging.The olmic contact mechanisms and carrier transport charactistics are discussed in light of the measurements of curront-vol-tage, specific contact resistance and ion microprobe. During the instant of capacitor discharging, the multi-componnt-alloy and the high resistivity ptype silicon wafer are inter-dissoluted at interface by high energj power generated from eletrical sparking, when the inter-dissoluted material is cooliog down,the high concentration active acceptor element is resolved from silicon, thereby turning the original high resistivity silicon into p~ at interface and effecting ohmic contact. The measurements of specific contact resistance at different temparetures combined with the calculation of doping dependence show that the transport current passing through the metal-semicondutor silicon is caused by the thermionic-field emission mechanism and the main transprt process is the tunneling of carriers through barriers.