Distributed electro-thermal RF-LDMOS model

Abstract

To develop an accurate RF-LDMOS large signal model,temperature distribution across a multi-finger 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.