Fabrication of High Speed GaN-based Transistors and DC-to-DC Converters.

下一代5G无线通信系统将需要对射频功率放大器（PA）进行大幅更改，以满足极高的传输数据速率要求（比4G高10倍以上）。此外，5G系统要求低功耗，但具有固定电压电源的传统PA随着频率的增加而效率低下。另一方面，具有较低能量损耗的电压可变PA具有满足5G需求的潜力。然而，PA缺乏高开关速度（> 100 MHz）的可变电压电源，这对高频系统设计提出了挑战。该项目旨在使用由氮化镓（GaN）半导体制成的电子开关器件实现超高开关速度（200 MHz）和高效率（>80%）的电压电源，用于下一代PA。将制造利用多栅极结构的新型GaN器件架构，以减少高速操作的电压切换时间和损耗。将进行模拟和表征，以了解器件物理和开关行为。将设计用于电压供应中的拟议GaN器件的新型电子控制电路。最后，将控制电路与GaN器件集成在单个芯片中，以减少不必要的寄生，并提高电压电源的开关性能，以满足5G系统的需求。

Next generation 5G wireless communication systems will require dramatic changes in the radio-frequency power amplifiers (PA) to meet the very high transfer data rate requirements (>10x higher than 4G). In addition, the 5G systems demand low power consumption but the conventional PA with a fixed voltage supply have poor efficiency with increasing frequency. Voltage-variable PA with lower energy losses, on the other hands, have potential to meet the 5G demands. However, lack of high switching speed (>100MHz) variable-voltage supply for the PA presents a challenge for high frequency system design.This project aims to realise ultra-high switching speed (200MHz) and high efficiency (>80%) voltage supplies using electronic switching devices made from gallium nitride (GaN) semiconductor for the next generation PA. Novel GaN device architecture which utilises multiple-gate structures will be fabricated to reduce voltage switching times and losses for high speed operations. Simulations and characterisations will be performed to understand the device physics and switching behaviours. Novel electronic control circuits for the proposed GaN devices in the voltage supplies will be designed. Finally, integration of the control circuits with GaN devices in a single chip will be carried out to reduce the unwanted parasitic and to boost the voltage supplies' switching performance to meet the 5G system demands.