Many materials systems are currently under consideration as potential replacements for SiO2 as the gate dielectric material for sub-0.1 μm complementary metal–oxide–semiconductor (CMOS) technology. A systematic consideration of the required properties of gate dielectrics indicates that the key guidelines for selecting an alternative gate dielectric are (a) permittivity, band gap, and band alignment to silicon, (b) thermodynamic stability, (c) film morphology, (d) interface quality, (e) compatibility with the current or expected materials to be used in processing for CMOS devices, (f) process compatibility, and (g) reliability. Many dielectrics appear favorable in some of these areas, but very few materials are promising with respect to all of these guidelines. A review of current work and literature in the area of alternate gate dielectrics is given. Based on reported results and fundamental considerations, the pseudobinary materials systems offer large flexibility and show the most promise toward success...

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High-κ gate dielectrics: Current status and materials properties considerations

Learn the basic properties and designs of modern VLSI devices, as well as the factors affecting performance, with this thoroughly updated second edition. The first edition has been widely adopted as a standard textbook in microelectronics in many major US universities and worldwide. The internationally-renowned authors highlight the intricate interdependencies and subtle tradeoffs between various practically important device parameters, and also provide an in-depth discussion of device scaling and scaling limits of CMOS and bipolar devices. Equations and parameters provided are checked continuously against the reality of silicon data, making the book equally useful in practical transistor design and in the classroom. Every chapter has been updated to include the latest developments, such as MOSFET scale length theory, high-field transport model, and SiGe-base bipolar devices.

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Fundamentals of Modern VLSI Devices

The compelling demand for higher performance and lower power consumption in electronic systems is the main driving force of the electronics industry's quest for devices and/or architectures based on new materials. Here, we provide a review of electronic devices based on two-dimensional materials, outlining their potential as a technological option beyond scaled complementary metal-oxide-semiconductor switches. We focus on the performance limits and advantages of these materials and associated technologies, when exploited for both digital and analog applications, focusing on the main figures of merit needed to meet industry requirements. We also discuss the use of two-dimensional materials as an enabling factor for flexible electronics and provide our perspectives on future developments.

Electronics based on two-dimensional materials

Power dissipation is a fundamental problem for nanoelectronic circuits. Scaling the supply voltage reduces the energy needed for switching, but the field-effect transistors (FETs) in today's integrated circuits require at least 60 mV of gate voltage to increase the current by one order of magnitude at room temperature. Tunnel FETs avoid this limit by using quantum-mechanical band-to-band tunnelling, rather than thermal injection, to inject charge carriers into the device channel. Tunnel FETs based on ultrathin semiconducting films or nanowires could achieve a 100-fold power reduction over complementary metal-oxide-semiconductor (CMOS) transistors, so integrating tunnel FETs with CMOS technology could improve low-power integrated circuits.

Tunnel field-effect transistors as energy-efficient electronic switches

Electron and ambipolar transport in organic field-effect transistors.

This paper presents the current state of understanding of the factors that limit the continued scaling of Si complementary metal-oxide-semiconductor (CMOS) technology and provides an analysis of the ways in which application-related considerations enter into the determination of these limits. The physical origins of these limits are primarily in the tunneling currents, which leak through the various barriers in a MOS field-effect transistor (MOSFET) when it becomes very small, and in the thermally generated subthreshold currents. The dependence of these leakages on MOSFET geometry and structure is discussed along with design criteria for minimizing short-channel effects and other issues related to scaling. Scaling limits due to these leakage currents arise from application constraints related to power consumption and circuit functionality. We describe how these constraints work out for some of the most important application classes: dynamic random access memory (DRAM), static random access memory (SRAM), low-power portable devices, and moderate and high-performance CMOS logic. As a summary, we provide a table of our estimates of the scaling limits for various applications and device types. The end result is that there is no single end point for scaling, but that instead there are many end points, each optimally adapted to its particular applications.

/pdf/device-scaling-limits-of-si-mosfets-and-their-application-299ftwsxth.pdf

Device scaling limits of Si MOSFETs and their application dependencies

SRAM cell stability will be a primary concern for future technologies due to variability and decreasing power supply voltages. 6T-SRAM can be optimized for stability by choosing the cell layout, device threshold voltages, and the /spl beta/ ratio. 8T-SRAM, however, provides a much greater enhancement in stability by eliminating cell disturbs during a read access, thus facilitating continued technology scaling. We demonstrate the smallest 6T (0.124/spl mu/m/sup 2/ half-cell) and full 8T (0.1998/spl mu/m/sup 2/) cells to date.

https://www.bioee.ee.columbia.edu/courses/upload/Bibliography/chang_vlsitech_2005.pdf?origin=publication_detail

Stable SRAM cell design for the 32 nm node and beyond

In this paper we present a generalized scaling theory which allows for an independent scaling of the FET physical dimensions and applied voltages, while still maintaining constant the shape of the electric-field pattern. Thus two-dimensional effects are kept under control even though the intensity of the field is allowed to increase. The resulting design flexibility allows the design of FET's with quarter-micrometer channel length to be made, for either room temperature or liquid-nitrogen temperature. The physical limitations of the scaling theory are then investigated in detail, leading to the conclusion that the limiting FET performances are not reached at the 0.25-µm channel length. Further improvements are possible in the future, provided certain technology breakthroughs are achieved.

Generalized scaling theory and its application to a &#188; micrometer MOSFET design

A guideline for scaling of CMOS technology for logic applications such as microprocessors is presented covering the next ten years, assuming that the lithography and base process development driven by DRAM continues on the same three-year cycle as in the past. This paper emphasizes the importance of optimizing the choice of power-supply voltage. Two CMOS device and voltage scaling scenarios are described. One optimized for highest speed and the other trading off speed improvement for much lower power. It is shown that the low power scenario is quite close to the original constant electric-field scaling theory. CMOS technologies ranging from 0.25 /spl mu/m channel length at 2.5 V down to sub-0.1 /spl mu/m at 1 V are presented and power density is compared for the two scenarios. Scaling of the threshold voltage along with the power supply voltage will lead to a substantial rise in standby power compared to active power and some tradeoffs of performance and/or changes in design methods must be made. Key technology elements and their impact on scaling are discussed. It is shown that a speed improvement of about 7/spl times/ and over two orders of magnitude improvement in power-delay product (mW/MIPS) are expected by scaling of bulk CMOS down to the sub-0.1 /spl mu/m regime as compared with today's high performance 0.6 /spl mu/m devices at 5 V. However, the power density rises by a factor of 4/spl times/ for the high-speed scenario. The status of the silicon-on-insulator (SOI) approach to scaled CMOS is also reviewed, showing the potential for about 3/spl times/ savings in power compared to the bulk case at the same speed. >

CMOS scaling for high performance and low power-the next ten years

A carrier for a semiconductor component is provided having passive components integrated in its substrate. The passive components include decoupling components, such as capacitors and resistors. A set of connections is integrated to provide a close electrical proximity to the supported components.

R.H. Dennard

Papers

Device scaling limits of Si MOSFETs and their application dependencies

Stable SRAM cell design for the 32 nm node and beyond

Generalized scaling theory and its application to a ¼ micrometer MOSFET design

CMOS scaling for high performance and low power-the next ten years

High density chip carrier with integrated passive devices

R.H. Dennard

Papers

Device scaling limits of Si MOSFETs and their application dependencies

Stable SRAM cell design for the 32 nm node and beyond

Generalized scaling theory and its application to a &#188; micrometer MOSFET design

CMOS scaling for high performance and low power-the next ten years

High density chip carrier with integrated passive devices

Generalized scaling theory and its application to a ¼ micrometer MOSFET design