Jeff J. Xu

A 25-nm gate-length FinFET transistor module for 32nm node

FinFET is the most promising double-gate transistor architecture [1] to extend scaling over planar device. We present a high-performance and low-power FinFET module at 25 nm gate length. When normalized to the actual fin perimeter, N-FinFET and P-FinFET have 1200 and 915 µA/µm drive current respectively at 100nA/µm leakage under 1V. To our knowledge this is the best FinFET drive current at such scaled gate length. This scaled gate length enables this FinFET transistor for 32nm node insertion. With aggressive fin pitch scaling, the effective transistor width is approximately 1.9X and 2.7X over planar for typical logic and SRAM on the same layout area (i.e., silicon real estate). Due to superior electrostatics and reduced random dopant fluctuation, this high drive current can be readily traded with VDD scaling for low power.

A low operating power FinFET transistor module featuring scaled gate stack and strain engineering for 32/28nm SoC technology

We show that FinFET, a leading transistor architecture candidate of choice for high performance CPU applications [1–3], can also be extended for general purpose SoC applications by proper device optimization. We demonstrate superior, best-in-its-class performance to our knowledge, as well as multi-Vt flexibility for low-operating power (LOP) applications. By high-k/metal-gate (HK/MG) and process flow optimizations, significant drive current (ION) improvement and leakage current (IOFF) reduction have been achieved through equivalent oxide thickness (EOT) scaling and carrier mobility improvement. N-FinFET and P-FinFET achieve, when normalized to Weff (Weff=2xHf+Wf), ION of 1325 µA/µm and 1000 µA/µm at 1 nA/µm leakage current under VDD of 1 V, and 960 uA/um and 690 uA/um at 1 nA/um under Vdd of 0.8V, respectively. This FinFET transistor module is promising for a 32/28nm SoC technology.

A novel multi deposition multi room-temperature annealing technique via Ultraviolet-Ozone to improve high-K/metal (HfZrO/TiN) gate stack integrity for a gate-last process

ALD HfZrO high-K fabricated by novel multi deposition multi annealing (MDMA) technique at room temperature in Ultraviolet-Ozone (UVO) ambient is systematically investigated for the first time via both physical and electrical characterization. As compared to the reference gate stack treated by conventional rapid thermal annealing (RTA) @ 600°C for 30 s (with PVD TiN electrode), the devices receiving MDMA in UVO demonstrates: 1) more than one order of magnitude leakage reduction without EOT penalty at both room temperature and an elevated temperature of 125°C; 2) much improved stress induced degradation in term of leakage increase and flat band voltage shift (both room temperature and 125°C); 3) enhanced dielectrics break-down strength and time-dependent-dielectric-breakdown (TDDB) life time. The improvement strongly correlates with the cycle number of deposition and annealing (D&A, while keeping the total annealing time and total dielectrics thickness as the same). Scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) analysis suggest both oxygen vacancies (Vo) and grain boundaries suppression in the MDMA treated samples are likely responsible for the device improvement. The novel room temperature UVO annealing is promising for the gate stack technology in a gate last integration scheme.