磷化銦鎵/砷化鎵異質接面電晶體安全操作範圍之二維模擬

Abstract

在此論文中我們使用了Sentaurus TCAD這套非常強大的半導體模擬軟體來進行磷化銦鎵/砷化鎵異質接面電晶體安全操作範圍之二維模擬。此模擬中我們除了建立與實際元件接近的結構之外並整合了許多異質接面電晶體所需具備的重要物理機制例如自發熱效應、衝擊離子化等。經過不斷地測試與參數校正後模擬結果與實際元件量測所得之安全操作範圍有相同的趨勢，在直流操作下安全操作範圍分成明顯地兩個區域，一個是高電壓小電流的區域另一個是低電壓大電流的區域。藉由分析元件的二維分布圖我們得出在高電壓小電流區域導致元件損壞主因是自發熱效應；在低電壓大電流區域損壞主因是Kirk effect引致之崩潰效應。除此之外射極電阻對安全操作範圍的影響與其他相關的重要議題也會被列入討論。

In this thesis, we use the Sentaurus TCAD, a very powerful simulation tool for semiconductor devices, to study the safe operating area (SOA) of InGaP/GaAs heterojunction bipolar transistors. In the simulation, we not only build the structure resembling real devices but also integrate many important physical mechanisms of heterojunction bipolar transistors such as self-heating, impact ionization, etc. After a lot of tests and corrections of parameters, the simulation results capture all the features of the measured SOA. The SOA during DC operation was found to have two distinct regions. One is the high voltages and low currents region and the other is the low voltages and high currents region. By analyzing the 2D plot of simulated devices, we can see that at high voltages and low currents region the device failure is controlled by the self-heating effect, but at the low voltages and high currents region the failure is governed by the impact ionization because of the Kirk effect induced breakdown. The influence of emitter resistance and other factors that are important to SOA are also discussed.