| 摘要 |
PURPOSE:To make highly reliable ohmic contact easily feasible by a method wherein a metal hardly reactive to both Au and Ni as well as to Si is laid between Au and Ni. CONSTITUTION:Both a p type base region 3 and an n type emitter region 4 are diffused in a wafer. After the diffusion process, an SiO2 film 12 of the base and emitter regions 3, 4 is selectively removed to form surface elements and then processed by Al evaporation to form a base electrode 5 and an emitter electrode 6. Then the backside of this wafer is ground conforming to specified thickness. Firstly Au containing e.g. Sb is evaporated on the backside. Secondly Ta 9 is evaporated further to evaporate an Ni 10 and an Ag 11 successively. Thirdly this wafer is heattreated using an enert gas or H2 gas at the temperature around 300-500 deg.C. At this time, Au containing Sb is alloyed with Si to form an Au-Si alloy 8. Finally the wafer may be divided into individual chips. |
