14-nm FinFET Technology for Analog and RF Applications

This paper describes the features and performance of an analog and RF device technology development on a 14-nm logic FinFET platform. An optimized single-side gate contact RF device layout shows a ${F}_{t}/{F}_{\text {max}}$ of 314/180 GHz and 285/140 GHz for ${N}$ and PFinFET device, respectively. The double-side gate contact structure with contact on either end of active gate enhances the peak ${F}_{\text {max}}$ performance to 227 and 195 GHz for both ${N}$ and PFinFET devices, respectively. A significant boost in the PFinFET RF performance is observed compared to 28-nm planar PFET, which is attributed to the source/drain SiGe epitaxy stressor that results in higher hole carrier mobility. On the other hand, the thin channel body of FinFET structure facilitates a better electrostatic control of gate over the channel region and hence suppresses short channel effects including the drain-induced barrier lowering. Consequently, a significantly higher self-gain ( ${G}_{m}/{G}_{\text {ds}})~40$ and 34 for both NFinFET and PFinFET is achieved. In addition, N/PFinFETs demonstrate superior 1/f noise of 17/35 fV $^{2}\mu \text{m}^{2}$ /Hz at 1 kHz compared to 171/106 fV $^{\mathrm {\mathbf {2}}}\mu \text{m}^{2}$ /Hz of 28-nm planar N/PFETs. To extend the low-voltage operation and power saving of FinFET RF platform, ultralow ${V}_{t}$ N/PFinFETs in the range of 50 mV ${V}_{t}\text{s}$ are also developed. Furthermore, a deep n-well process is added to the platform to provide device and circuit isolation from substrate and supply noise, while realizing the creation of new devices such as vertical NPN, PCAP, and high breakdown voltage deep n-well junction diodes. Overall, a superior ${F}_{t}/{F}_{\textsf {max}}$ , high self-gain, low 1/f noise, and robust substrate isolation characteristics extend the capability of this new 14-nm FinFET technology to the analog and RF circuit applications.