ALD-Growth High-K Oxide GaN MOSFET and Its Application on High Power Microwave Switch

High power switch is a power electronics technology which was applied to power converter and energy transformer in consumer electronics. Owing to the power converter is now operated at high frequency leading to the reduction the size and the weight in whole power module. However, these technologies were demonstrated typically. GaN is a wide bandgap compound semiconductor material which is widely used for optical electronics and microwave power electronics applications. For high power switch application, the characteristics of GaN are beneficial for improving high frequency and high efficiency power switch owing to its low leakage current, high thermal dissipation factor, and high mobility compared to conventional Si process. These benefits provide low power dissipation, small over shoot voltage, and high efficiency of power electronic circuits. This project is primary to further improve conventional GaN HEMT structure by using GaN MOSFET with high stability and high dielectric constant insulator. At the begin, we will apply ALD-growth high-k Gd2O3, Pr2O3, HfO2 insulators (ε=10~20) in our GaN MOSFET to enhance the gate to channel charge control ability and reduce the channel to gate leakage current at high power swing. This design is very good for suppressing the power consumption at off-state operation and harmonics distortion. For the second year, the high power transistor with Cu interconnection will be demonstrated because of the low resistivity and high thermal dissipation for Cu metal. In this year, the device reliability and the interface mechanism between GaN and Cu will be investigated by 85-85 evaluation (temperature = 85 oC and humidity = 85 % ) and SIMS analysis. Besides, the ion-implantation technology will be also adopted for improving the deep substrate leakage current and power device gate yield. For the last year, we will demonstrate a high power switch at 2 Watt continuous wave operation.

Project ID:PB9801-2176
External Project ID:NSC97-2221-E182-048-MY3