鈀/鍺/鉬(鉻)/銅歐姆接觸應用在磷化銦鎵/砷化鎵異質接面雙載子電晶體

Abstract

本篇論文探討在磷化銦鎵/砷化鎵異質接面雙載子電晶體上使用鈀/鍺/鉬/銅及鈀/鍺/鉻/銅作為歐姆接觸金屬的可行性,其中金屬鉬與鉻是作為歐姆接觸中銅的擴散組絕層. 在鈀/鍺/鉬/銅與鈀/鍺/鉻/銅歐姆接觸的材料分析中,兩種結構在350°C的溫度下皆是穩定的.熱穩定測試中,在300°C,20小時退火後,以鉬作為擴散阻絕層的歐姆接觸仍然穩定,以鉻作為擴散阻絕層的歐姆接觸電阻則有上升的趨向.材料分析也和此結果相符. 在元件的製造上,鉬作為擴散阻絕層的歐姆接觸將運用在 磷化銦鎵/砷化鎵異質接面雙載子電晶體上,經過250°C 二十四小時的退火處理,並和使用金為毆姆接觸的元件電性比較,兩者元件的電性幾乎沒有改變

In this paper, the feasibilities of using the Pd/Ge/Mo/Cu and Pd/Ge/Cr/Cu layers as the ohmic contacts on InGaP/GaAs HBTs were studied. Refractory metal Mo, and Cr were used as the diffusion barrier and applied to the ohmic contact applications. For the material analysis of the Pd/Ge/Mo/Cu and Pd/Ge/Cr/Cu ohmic contacts, both structures were thermally stable up to 350°C. For the electrical characteristic measurement, the contact resistance of the contact with Mo as the diffusion barrier was stable up to 300°C, 20 hours annealing, while the contact resistance of the contact with Cr as the diffusion barrier increased after the 300°C, 20 hours annealing. The results are in consistent with the materials analysis. For HBT device fabrication, Mo and Cr were chosen as the diffusion barrier for copper ohmic contact. A gallium arsenate (GaAs) Hetronjunction Bipolar Transistor (HBT) with copper-metallized ohmic contact was successfully developed. Sputtered Mo was used as the diffusion barrier. Comparing the HBT devices with Cu metallization ohmic contact with devices made with traditional Au ohmic contact, both devices show little change in device performance after annealing at 2500C for 24 hours.