为了准确的测量GaN HEMT的热阻参数,在两种不同的管壳接触热阻条件下,利用经过改进的显微红外热像仪测量了GaN HEMT的降温曲线.采用结构函数算法对两种降温曲线进行分析,得到了反映器件各层材料热阻的积分结构函数曲线.当管壳接触层由空气变化为导热硅脂时,积分结构函数曲线发生了变化.通过结构函数曲线能够明确区分被测件不同层的热阻.可以将被测件的分成7层结构,与器件真实结构基本一致.%In order to measure the thermal resistance of GaN HEMT accurately,under two different thermal contact conditions between case and fixture,cooling curves were measured using an improved IR microscope,respectively. Structure function method was used to deal with the cooling curves,the cumulative structure function curves which show the thermal resistances of layers in GaN HEMT were obtained. When the material between case and fixture was changed from air to thermal grease,the cumulative structure function curves changed obviously. Thermal resistance of different layers of DUT can be distinguished from structure function curves,the DUT was divided into a 7 layers structure,that was approximately consistent with the real device structure.
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