RF LDMOS power transistor for multi-carrier GSM base station

In this paper, we present an optimized RF LDMOS transistor structure based on modified CMOS technology. The drift region is improved to reduce the change rate of the output capacitor of the transistor and ameliorate the linearity of power amplifier. Hot Carrier Injection (HCI) is alleviated by reducing the electric field at the gate edge near the drain by optimizing the field plate and the doping distribution of the channel. Excellent characterizations are achieved for Multi-Carrier GSM Base Station applications with linear gain of 20dB at 960MHz, high efficiency of 75% and 52dBm of saturated power. A load pull system is set up to test the optimum impedance points of the transistor, and the RF performance is evaluated by designing internal matching network and a demonstration board.