Veeraraghavan Dhandapani

Embedded SiGe S/D PMOS on thin body SOI substrate with drive current enhancement

We report for the first time PMOS drive current enhancement with in-situ boron doped SiGe incorporation in recessed S/D regions for devices built on thin body SOI substrate. For P-channel PD-SOI devices with 450 A silicon on insulator and 38nm gate length, 35% linear drain current enhancement and 20% saturation drain current improvement have been achieved with this approach. Device integration and performance improvement are discussed below.

Strain-Enhanced CMOS Through Novel Process-Substrate Stress Hybridization of Super-Critically Thick Strained Silicon Directly on Insulator (SC-SSOI)

This paper describes a biaxial-uniaxial hybridized strained CMOS technology achieved through selective uniaxial relaxation of thick SSOI, dual-stress nitride capping layer, and embedded SiGe source/drain. Through novel strain engineering, nFET/pFET Idsat enhancements as high as 27%/36% have been achieved for sub-40nm devices at 1V with 30% reduction in gate leakage current, while introducing minimum process complexity. This work demonstrates the scalability of SC-SSOI and its advantages over pure biaxial and single uniaxial strained Si technologies

Metrology Challenges for 45-nm Strained-Si Device Technology

The semiconductor industry has maintained its historical exponential improvement in performance by aggressively scaling transistor dimensions. However, as devices approach sub-100-nm dimensions, scaling becomes more challenging and new materials are required to overcome the fundamental physical limitations imposed by existing materials. For example, as power supply voltages continue to decrease with successive scaling, enhancing carrier mobility using biaxially tensile-stressed Si on relaxed SiGe on SOI and on bulk substrates has become a viable option to sustain continual drive current increase without traditional scaling. Although the addition of strained-Si to conventional MOSFET devices is compatible with existing mainstream CMOS process technology, there are new device and process integration challenges, wafer quality monitoring demands, and stringent requirements for film morphology and strain uniformity, imposing new demands on material characterization. Material requirements for strained-Si CMOS devices include having uniform SiGe thickness, Ge composition, and strain distribution. These are required to maintain uniform device performance as well as low defect density for high minority carrier lifetimes and transconductance, as well as low surface roughness to minimize the impact of interface scattering on carrier mobilities. The parameters of interest in strained-Si CMOS technology include SiGe and Si channel thickness, Ge composition, strain, dislocation density, interface quality, and roughness. Nondestructive inline metrology techniques include spectroscopic ellipsometry for film thickness and Ge composition, X-ray reflectivity for thickness, density, and roughness measurements, X-ray fluorescence for Ge composition, UV-Raman spectroscopy for channel strain characterization, IR photoluminescence for defect detection, and X-ray diffraction for both Ge content and strain measurement. While most of these techniques are well established in the semiconductor industry, some will require development for application to volume manufacturing. This paper will focus on various metrology approaches used in strained-Si CMOS devices

Metrology Challenges for 45 nm Strained‐Si Devices

The semiconductor industry has sustained its historical exponential performance gains by aggressively scaling transistor dimensions. However, as devices approach sub‐100 nm dimensions, scaling becomes more challenging and new materials are required to overcome the fundamental physical limits imposed by existing materials. For example, as power supply voltages continue to decrease with successive scaling, enhanced carrier mobility using biaxially tensile‐strained‐Si on SOI or on bulk substrates have become viable options to sustain continual drive current increases without traditional scaling. Although the addition of strained‐Si to conventional MOSFET devices is compatible with existing mainstream CMOS process technology, there are new device and process integration challenges, wafer quality monitoring demands, and stringent requirements for film morphology and strain uniformity, imposing new demands on material characterization. Material requirements for strained‐Si CMOS devices include homogeneous Si or...

An Embedded Silicon-Carbon S/D Stressor CMOS Integration on SOI with Enhanced Carbon Incorporation by Laser Spike Annealing

We report a CMOS-compatible embedded silicon-carbon (eSiC) source/drain stressor technology with NMOS performance enhancement. The integration includes up to 2.6% substitutional carbon (Csub) epitaxial Si:C and laser spike annealing (LSA) for increased Csub incorporation. 26% channel resistance (Rch) reduction and 11% Idlin-Ioff enhancement for 0.5% Csub and 60% Rch reduction for 2.2% Csub are demonstrated.

Uniaxial and Biaxial Strain for CMOS Performance Enhancement

Uniaxial stressors have been mainly employed for boosting PMOS performance, while it is more difficult to increase NMOS performance using tensile stressors. This results in changing the n:p ratio, which requires circuit layout changes. Enhancing both NMOS and PMOS performance to retain the same n:p ratio is desirable. Interactions between biaxial lattice strain, uniaxial relaxation, process-induced stressor and channel orientation have been optimized to achieve the desired stress configurations for enhancing both short-channel SSOI NMOS and PMOS devices

Integration challenges of new materials and device architectures for IC applications

In this paper, we will detail the issues with new materials being introduced into CMOS devices and present some potential solutions to enable high performance and low power CMOS for the 65nm node and beyond.

Characteristic Study of SOI eSiGe Techonology

This paper presents a detailed study of SOI source/drain embedded SiGe (eSiGe) technology with a focus on parasitic characteristics. It shows that eSiGe can appreciably suppress on-state floating body effect and improve device exterior resistance. Although eSiGe only physically addresses P-FET, junction capacitances of both P- and N-FETs can be impacted.