綠能功率電子元件穩態與暫態熱管理研究

Abstract

AlGaN/GaN功率晶體，相較於傳統以矽為主體的功率元件，具有高的電子移動率、高崩潰電壓的特徵，適合操作在高功率、高頻率下，但因其熱傳導特性較差，功率晶體內二維電子氣層的通道溫度也隨元件操作下產生的自發性熱效應攀升，進而降低AlGaN/GaN功率晶體的效能及可靠度。為了要達到有效的熱管理，必須要掌握AlGaN/GaN功率晶體，進而設計出適合此元件之封裝結構，並對此結構進行結構熱分析。本研究使用Icepak熱模擬軟體針對Cascode AlGaN/GaN功率模組進行穩態暫態熱模擬分析，估測Cascode AlGaN/GaN功率模組隨時間操作下的暫態溫度變化，透過Transient Dual Interface Measurement Procedure，方式模擬Cascode AlGaN/GaN功率模組量測穩態熱阻最後利用結構函數理論分析每一層結構之熱阻熱容變化，並透過業界量測實驗與模型互相驗證，藉此達到有效的封裝熱管理。 此外，本研究使用串疊電路，結合AlGaN/GaN晶體元件的高速開關特性及Low Voltage MOSFET元件形成常閉型(normally-off)開關，可取代現行MOSFET功率元件。透過此電路結構設計可保護AlGaN/GaN晶體元件避免損換，並利用此設計使AlGaN/GaN晶體元件利用能更加廣泛。

AlGaN/GaN power transistors, compared to conventional silicon-based transistors, have characteristics of high electron mobility, high breakdown voltage, suitable for operating at high power and high frequency conductions. Temperature has significant influence on both performance and reliability of semiconductor devices. However, the thermal conductivity of GaN (130W/m-K) is lower than silicon carbide(490W/m-K).The increasing of the active region temperature will reduce crucial device parameters. Thus, the packaging design of the component must have good thermal management. In this research, the Transient Dual Interface Measurement Procedure to calculate steady state thermal resistance through simulation is proposed. We also present the short time thermal transient measurement method and the structure function to analyze packed GaN transistor. Finally, T3ster measurement experiment and the result of simulation are compared to verify the correctness of proposed thermal simulation procedure for power device packaging design.