以電性參數估測氮化鎵功率元件之元件通道溫度 與暫態熱分析

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，進而導致降低元件的效能及可靠度。為了達到有效的AlGaN/GaN功率晶體的熱管理，必須要掌握AlGaN/GaN功率晶體通道溫度，以及元件封裝結構熱分析。本研究使用電性參數估測法，建立元件電性參數量測資料曲線，推估元件之通道溫度，並結合紅外線熱分析儀進行分析比較，進一步估測AlGaN/GaN功率晶體隨時間操作下的暫態溫度變化，並利用結構函數理論分析元件內部封裝層之熱阻熱容關係，藉此達到有效的封裝熱管理。 本研究對元件之暫態熱分析與材料理論值，以及使用JEDEC STANDARD標準量測法的T3ster代測結果進行比較，其元件熱阻及熱容分析結果皆相符，因此可確認本暫態分析法的準確性，未來在元件的封裝熱阻量測上能藉此分析元件封裝的優劣，進而針對封裝及內部進行改善。

The high power dissipation for AlGaN/GaN HEMT can result in a substantial self-heating effect, which will reduce the performance reliability. Thermal transient measurement for the characterization of IC packages is becoming increasingly important. The evaluation of thermal resistance constitution for packaged AlGaN/GaN high electron mobility transistor (HEMT) by structure function method is proposed in this paper. The evaluation is based on the transient heating measurement of the AlGaN/GaN HEMT by temperature sensitive parameter (TSP) method. We build a database of these temperature sensitive parameters within a variety of experimental situations, and combine Infrared thermography to verify the channel temperature of cascode GaN power transistor. With the help of structure function, partial thermal resistances and partial thermal capacitances in a heat flow path can be determined not only inside the device package but also outside electronic components with high accuracy. This result was verified by comparing the results of a cascode GaN HEMT device measurement by T3Ster.