用于RF-LDMOS的分布式电热耦合模型

Distributed electro-thermal RF-LDMOS model

为建立精确的RF-LDMOS大信号模型,提出分布式电热耦合模型.通过采用三维镜像法简单计算单指条的温度分布,进一步使用叠加原理计算得到多指条温度的横向分布,此模型的解析式使用热矩阵方程来表示,通过对计算结果的拟合提取热模型参数.与传统热模型相比,此热模型通过使用指条之间的互热阻表征横向热流的相互作用,同时以分布的热RC网络为多指条建模,代替平均热电阻网络模型.计算结果表明,使用分布式电热耦合模型不仅能更精确反映温度的分布效应,而且可用于等比例缩放时更准确的预测平均热电阻.

To develop an accurate RF-LDMOS large signal model, temperature distribution across a multifinger device was researched. Using the three dimensional image method, temperature distribution across a finger was easily calculated. Furtherly, for multiple fingers, lateral temperature distribution could be obtained under the superposition principle. A thermal matrix was used to describe the model and the thermal parameters were obtained by fitting with the calculation results. Compared with the traditional thermal model, this model can be used to characterize the heat transferring horizontally by using mutual thermal resistances between fingers and the average thermal resistance network is replaced by distributed thermal RC network to model the multi-fingers. The calculation results show that it can present the temperature distribution and predict the average thermal resistance of scaling devices more accurately.