Kevin McStay

A manufacturable dual channel (Si and SiGe) high-k metal gate CMOS technology with multiple oxides for high performance and low power applications

Band-gap engineering using SiGe channels to reduce the threshold voltage (VTH) in p-channel MOSFETs has enabled a simplified gate-first high-к/metal gate (HKMG) CMOS integration flow. Integrating Silicon-Germanium channels (cSiGe) on silicon wafers for SOC applications has unique challenges like the oxidation rate differential with silicon, defectivity and interface state density in the unoptimized state, and concerns with Tinv scalability. In overcoming these challenges, we show that we can leverage the superior mobility, low threshold voltage and NBTI of cSiGe channels in high-performance (HP) and low power (LP) HKMG CMOS logic MOSFETs with multiple oxides utilizing dual channels for nFET and pFET.

A 0.039um 2 high performance eDRAM cell based on 32nm High-K/Metal SOI technology

We present industrys smallest eDRAM cell and the densest embedded memory integrated into the highest performance 32nm High-K Metal Gate (HKMG) SOI based logic technology. The cell is aggressively scaled at 58% (vs. 45nm) and features the key innovation of High-K Metal (HK/M) stack in the Deep Trench (DT) capacitor. This has enabled 25% higher capacitance and 70% lower resistance compared to conventional SiON/Poly stack at matched leakage and reliability. The HKMG access transistor developed in high performance optimized technology features sub 3fA leakage and well-controlled threshold voltage sigma of 40mV. The fully integrated 32Mb product prototypes demonstrate state of the art performance with excellent retention and yield characteristics. The sub 1.5ns latency and 2ns cycle time have been verified with preliminary testing whereas even better performance is expected with further characterization. In addition, the trench capacitors set the industry benchmark for the most efficient decoupling in any 32nm technology.

Performance analysis and modeling of deep trench decoupling capacitor for 32 nm high-performance SOI processors and beyond

In this paper, we present a systematic performance study and modeling of on-chip deep trench (DT) decoupling capacitors for high-performance SOI microprocessors. Based on system-level simulations, it is shown that the DT decoupling capacitors (decap) offer significant area advantage over the other two conventional decoupling capacitors - Metal-oxide-semiconductor (MOS) and Metal-Insulator-Metal (MIM). The fabrication process flow of DT decap is borrowed from regular eDRAM process and adds no additional process cost to processors that utilize large eDRAM cache [1]. We demonstrate that, with new process innovations such as introduction of High-k/metal gate and new plate doping methodology, there is significant reduction in equivalent series resistance (ESR) of the trench resulting in ~3.5X improvement in half capacitance frequency for 32nm node. Further, with 22nm technology, improved ESR, DT Decaps performance is significantly enhanced, hence showing that DT-decaps can be reliably used for technology beyond 32nm.

Transistor Matching and Fin Angle Variation in FinFET Technology

The introduction of FinFET architecture was expected to alleviate the issue of mismatch compared with planar technology, given the lower doping levels required. However, several authors have reported better mismatch results for planar technology suggesting additional challenges for FinFET architecture. An additional mechanism previously not considered arising from charge present at points of disturbance in the silicon lattice in tapering and wavering fins is shown to contribute to transistor mismatch. We show that including this mechanism improves the quantitative understanding of mismatch in FinFETs.

Revisiting the impact on sub-threshold regions in uniaxially-strained FETs

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