氮化鎵功率元件通道溫度之電性參數估測法研究

Abstract

AlGaN/GaN功率晶體，相較於傳統以矽為主體的積體電路，具有高的電子移動率、低消耗功率、高切換速度的特徵，適合操作在高功率、高頻率下。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。本研究使用元件性能參數量測法，建立元件性能參數量測實驗資料庫，利用此建立之資料庫，並結合紅外線熱分析儀，推估AlGaN/GaN功率晶體通到溫度，藉此可以掌握AlGaN/GaN功率晶體可操作的溫度範圍，達到有效的封裝熱管理。 此外，為了滿足高功率、高頻率電晶體元件之散熱需求，本研究提出新式複層封裝設計，利用多夾層方式提升熱散佚效率，對氮化鎵功率模組以氮化鋁絕緣陶瓷為基底，接合鎢銅片、覆銅陶瓷基板、凝膠、氮化鋁絕緣陶瓷上蓋版以達到複層散熱管理。並使用串疊電路，結合了氮化鎵電晶體元件的高速開關速度特性及Low Voltage MOSFET元件穩定的閘極開關，並利用此結構可保護氮化鎵電晶體元件避免其損壞與增加元件之穩定性，使氮化鎵電晶體元件利用更加廣泛。

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. The increasing of the active region temperature will reduce crucial device parameters. Therefore, accurate assessment and characterization of the thermal capabilities of GaN power transistors is critical for the development and design of high-density power applications. It is used as temperature sensitive parameters to determine the channel temperature at its normal working state by fast switch circuit technique. In this research, 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 AlGaN/GaN power transistor. In addition, in order to improve the thermal performance for GaN power transistors, this study proposed a novel multi-layer heat dissipation package including aluminum nitride ceramic substrate, Tungsten copper table, direct bonding copper, and aluminum nitride ceramic cover. By using cascode GaN structure, a 4-lead TO257 packaging of GaN and Low Voltage MOSFET can be operated in normally-off condition and provided a localized path for cooling the device.