A Wideband RF Power Amplifier in 45-nm CMOS SOI Technology With Substrate Transferred to AlN
A Wideband RF Power Amplifier in 45-nm CMOS SOI Technology With Substrate Transferred to AlN
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DOI：
10.1109/tmtt.2012.2223229
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发表时间：
2012-12-01
影响因子：
4.3
通讯作者：
Mohammadi, Saeed
中科院分区：
文献类型：
--
作者：
Chen, Jing-Hwa;Helmi, Sultan R.;Mohammadi, Saeed
采用标准的45纳米CMOS SOI技术，采用16个低击穿电压薄氧化物晶体管堆叠实现了宽带射频功率放大器（RF PA）。当PA在大电压波动下工作时，动态偏置和堆叠的组合可防止所有击穿机制，并且无需输出匹配网络即可实现接近50 ω的输出阻抗。采用后处理工艺，将CMOS SOI PA的导电Si衬底蚀刻掉，代之以半绝缘的氮化铝（AlN）衬底，以减少衬底寄生电容的影响，提高PA的性能。在1.5至2.6 GHz的- 3db带宽下，实现了1.8 GHz时12.2 dB的小信号增益。为了实现高可靠性工作，PA偏置15v电源和0.2 mA/mu m的小晶体管电流密度，提供30.2 dBm的饱和输出功率（P-SAT）和23.8%的峰值功率附加效率（PAE）。在较低的12 V电源电压下，在1.5 ~ 2.4 GHz的宽测量频率范围内，P-SAT和P-1 dB分别保持在27.9和24.8 dBm以上，峰值PAE在20%以上。在输出功率，效率和线性度方面，AlN衬底上的CMOS PA优于其Si对应物，尽管使用薄氧化物低击穿电压晶体管，但两种PA都具有良好的功率性能。
A wideband radio frequency power amplifier (RF PA) is implemented with a stack of 16 low-breakdown-voltage thin-oxide transistors in a standard 45-nm CMOS SOI technology. A combination of dynamic-biasing and stacking prevents all breakdown mechanisms when the PA operates under large voltage swings and facilitates an output impedance close to 50 Omega without a need for an output-matching network. Using a post-fabrication process, the conductive Si substrate of the CMOS SOI PA is etched away and replaced by a semi-insulating aluminum nitride (AlN) substrate to reduce the effect of substrate parasitic capacitances and improve the PA's performance. A small-signal gain of 12.2 dB at 1.8 GHz is achieved with a -3-dB bandwidth from 1.5 to 2.6 GHz. For high-reliability operation, the PA is biased with a 15-V power supply and a small transistor current density of 0.2 mA/mu m and delivers a saturated output power (P-SAT)of 30.2 dBm and a peak power-added efficiency (PAE) of 23.8%. For a wide range of measured frequencies from 1.5 to 2.4 GHz and under a lower supply voltage of 12 V, P-SAT and P-1 dB remain above 27.9 and 24.8 dBm, respectively, with peak PAE above 20%. In terms of output power, efficiency, and linearity, the CMOS PA on AlN substrate outperforms its Si counterpart, while both PAs deliver good power performance despite utilizing thin-oxide low-breakdown-voltage transistors.