Analysis And Optimization Of Static Characteristics Of RF High Power LDMOS

LDMOS transistor device is a new generation of integrated solid microwave power semiconductor device, which is the combination of semiconductor IC and microwave electronic technology. It is widely used as the component of power amplifiers in many domains, such as mobile communication, broadcasting, television, microwave relay, navigation, phased-array radar, etc. RF high power LDMOS, based on the traditional LDMOS, is the preferred device used in the RF amplifier of 3G base stations because of its high operating frequency up to P or L band and attractive ratio of performance and price.Static characteristic is a key criterion to evaluate the capability of RF high power LDMOS. Its performance has been improved greatly by a great deal of experiment, but the researches on its inner mechanism are reported rarely. Based on this background, this paper studies the static mechanism of RF high power LDMOS deeply from breakdown voltage and transconductance, by analyzing the results of the ISE TCAD simulation and actual chip tests. In detail, three aspects are discussed as follows.1) Breakdown Voltage Model: Analytical model of 2-D distribution of potential and electrical field in drift region of RESURF LDMOS is deduced. Based on it, a new breakdown voltage model of RESURF LDMOS is built.2) Breakdown Voltage Optimization: The relation of boundary curvature radius of drain region and breakdown voltage of RF high power LDMOS is analyzed, then a new method to optimize the performance by increasing the boundary curvature of drain region is discussed.3) Transconductance Model: The law of electron motion in the small size LDMOS is studied. It is pointed out that electron velocity usually achieves saturation both in the channel and drift region of RF high power LDMOS. Based on this fact, a new transconductance model of RF high power LDMOS is built.