While the selection of new "backbone" device structure in the era of post-planar CMOS is open to a few candidates, FinFET and its variants show great potential in scalability and manufacturability for nanoscale CMOS. In this paper we report the design, fabrication, performance, and integration issues of double-gate FinFET with the physical gate length being aggressively shrunk down to 10nm and the fin width down to 12nm. These MOSFETs are believed to be the smallest double-gate transistors ever fabricated. Excellent short-channel performance is observed in devices with a wide range of gate lengths (10similar to105nm). The subthreshold slopes of the 10nm gate length FinFETs are 125mV/dec for n-FET and 101mV/dec for p-FET, respectively. The DIBL's are 71mV/V for n-FET and 120mVN for p-FET, respectively. At 55nm gate length, the subthreshold slopes are 64mV/dec for n-FET and 68mV/dec for p-FET, which is very close to the ideal MOSFET behavior (at room temperature). The DIBL's are 11 mV/V for n-FET and 27mV/V for p-FET, respectively. All measurements were performed at a supply voltage of 1.2V. The observed short-channel behavior outperforms any reported single-gate silicon MOSFETs. Due to the (110) channel crystal orientation, hole mobility in the fabricated p-channel FinFET remarkably exceeds that in a traditional planar MOSFET. At 105nm gate length, p-channel FinFET shows a record-high transconductance of 633muS/mum at a V-dd of 1.2V. At extremely small gate lengths, parasitic R-sd in the narrow fin (proportionally scaled with L-g) influences the device performance. Working CMOS FinFET inverters are also demonstrated.