F等离子体处理增强型及耗尽型AlGaN/GaN HEMT集成SRAM单元电路和电平转换电路

我们设计并且制备了GaN基增强型/耗尽型（E/D 模）直接耦合6管静态随机存取存储器（SRAM）单元电路和电平转换电路。利用氟等离子处理工艺，使用适中的AlGaN势垒层厚度异质结材料，增强型和耗尽型铝镓氮/氮化镓 HEMTs被集成在了同一个晶片上。六管SRAM单元由对称的两个E/D模反相器和增强型开关管组成。在1V的工作电压下，SRAM单元电路的输出高电平和低电平分别为0.95V和0.07V。电平转换电路的工作电压为+6V和-6V，通过4个串联的镍-铝镓氮/氮化镓肖特基二极管使电压降低。通过轮流控制电平转换电路的两个反相器模块的开关状态，电平转换电路输出两路电压，分别为-0.5V和-5V。电平转换器的翻转电压为0.76V。SRAM单元电路和电平转换电路都能正确地工作，展现了氮化镓基E/D模数字和模拟集成电路的潜力。提出了几条设计上的考虑，以避免阈值电压的漂移对电路工作造成的影响。

Monolithically integrated enhancement/depletion-mode AlGaN/GaN HEMTsSRAM unit and voltage level shifter using fluorine plasma treatment

A GaN-based E/D mode direct-couple logic 6 transistors SRAM unit and a voltage level shifter were designed and fabricated. E-mode and D-mode AlGaN/GaN HEMTs were integrated in one wafer using fluorine plasma treatment and using a moderate AlGaN barrier layer heterojunction structure. The 6 transistors SRAM unit consists of two symmetrical E/D mode inverters and two E-mode switch HEMTs. The output low and high voltage of the SRAM unit are 0.95 and 0.07 V at a voltage supply of 1 V. The voltage level shifter lowers the supply voltage using four Ni-AlGaN Schottky diodes in a series at a positive supply voltage of 6 V and a negative supply voltage of -6 V. By controlling the states of inverter modules of the level shifter in turn, the level shifter offers two channel voltage outputs of -0.5 and -5 V. The flip voltage of the level shifter is 0.76 V. Both the SRAM unit and voltage shifter operate correctly, demonstrating the promising potential for GaN-based E/D mode digital and analog integrated circuits. Several considerations are proposed to avoid the influence of threshold voltage degradation of D-mode and E-mode HEMT on the operation of the circuit.