鎘元素在銻化銦內擴散與由其所製成相關元件之研究與分析

Abstract

本論文主要是採用兩段式高溫爐擴散方法, 將鎘元素擴散進入N-型銻化銦晶片內, 形 成P-N 接面, 然後以電容–電壓(C-V) 方法來分析擴散後鎘原子在銻化銦晶片內分佈 之情況及接面深度, 再用修正之Boltzmann-Matano方法來分析相關之擴散分布曲線, 並得到對應之擴散係數。 由上述擴散後之銻化銦晶片, 製作P-N 接面二極體, 並藉著改變二極體之工作溫度, 分別量測它的電流–電壓關係, 發現以低濃度銻化銦晶片(1×10 cm ) 製作之二極 體, 它具有很大的反向崩潰電壓(14伏特, 在77K 時), 而這個反向崩潰電壓隨二極體 之工作溫度(20-85K)降低而降低, 顯示出它的崩潰成因是屬於“雪崩崩潰(avalavche breakdown) ”。再由閘控二極體之電性分析, 可看出在反向電壓小於3 伏特時, 由 知反身電流是以“本質電流(bulk current)”為主。 由上述之結果可看出本論文內製成之二極體具有十分良好的“電流–電壓”特性, 在 這個基礎下, 所製作出之銻化銦金氧半場效電晶體更是具有高崩潰電壓(大於11伏特) 及良好的次臨限區電流等特性, 由之在場效電晶體中汲極(drain) 之電流–電壓特性 曲線中可觀察到飽合特性等, 這些都是在目前已發表之相關文獻中具有最好特性之元 件。

InSb p-n junction formed by Cd diffusion using a two7 temperature7 zone technique. The junction depth and diffusion profile were determined by analyzing the capacitance7 voltage measurements of the MIS diodes fabricated on the etched wafer. A modified Boltzmann7 Matano method was used to analyze the diffusion profile, diffusion coefficient as a function of carrier concentration was obtained. InSb junction diodes were then fabricated to study the leakage current and breakown mechanism. It was found that diodes fabricated on low carrier concentration substrates （圖表省略） have a rather large reverse breakdown voltage（14V at 77K）. The breakdown voltage decreased as the temperature was decreased, indicating that the mechanism responsible for the breakdown was an avalanche process. Gate controlled diodes were fabricated to study the surface effects. It was concluded that the reverse current was dominated by bulk current, instead of surface current, when the reverse bias voltage was below 3V. InSb MOS field7 effect7 transistors were also fabricated. The MOSFET exhibited high breakdown voltage, which enabled full observation of the current saturation region. Drain current7 voltage characteristics also showed good subthreshold behavior, having an on7 off ratio of. （圖表省略）