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

Silicon-based heterostructures have come a long way from the discovery of strain as a new and essential parameter for band structure engineering to the present state of electron and hole mobilities, which surpass those achieved in the traditional material combination by more than an order of magnitude and are rapidly approaching the best III - V heteromaterials. It is the purpose of this article to report on the most recent developments, and the performance level achieved to date in this material system, in a concise and critical manner. The first part of this review is concerned with the structural and electronic properties of the lattice-mismatched Si/SiGe heterostructure. Emphases are put on the effects of strain both on the band structure and on the band offsets, as well as on means to actually control the strain in a stack of heteroepitaxial layers. The second part is dedicated to the transport properties of low-dimensional carrier systems in Si/SiGe and Ge/SiGe heterostructures. The prospects and limitations of the different layer concepts are discussed in terms of scattering mechanisms and experimental results. This part also reviews the most recent magneto-transport experiments on quantum wires and quantum point contacts, which became possible by the enhanced mean free paths in these materials. The third part covers the device aspects of these high-mobility materials, which is of special interest, because silicon-based heterostructures can significantly enhance the performance level of contemporary Si devices without sacrificing the essential compatibility with standard Si technologies. The recent achievements in this application-driven research field, but also the foreseeable problems and limitations, are discussed, and an assessment of the possible role of such heterodevices in future microelectronic circuits is given.

http://iopscience.iop.org/article/10.1088/0268-1242/12/12/001/pdf

High-mobility Si and Ge structures

The silicon-germanium heterojunction bipolar transistor (SiGe HBT) is the first practical bandgap-engineered device to be realized in silicon. SiGe HBT technology combines transistor performance competitive with III-V technologies with the processing maturity, integration levels, yield, and hence, cost commonly associated with conventional Si fabrication. In the ten-and-one-half years since the first demonstration of a functional transistor, SiGe HBT technology has emerged from the research laboratory, entered manufacturing on 200-mm wafers, and is poised to enter the commercial RF and microwave market. State-of-the-art SiGe HBT's can deliver: (1) f/sub T/ in excess of 50 GHz; (2) f/sub max/ in excess of 70 GHz; (3) minimum noise figure below 0.7 dB at 2.0 GHz; (4) 1/f noise corner frequencies below 500 Hz; (5) cryogenic operation; (6) excellent radiation hardness; (7) competitive power amplifiers; and (8) reliability comparable to Si. A host of record-setting digital, analog, RF, and microwave circuits have been demonstrated in the past several years using SiGe HBT's, and recent work on passives and transmission lines on Si suggest a migratory path to Si-based monolithic microwave integrated circuits (MMIC's) is possible. The combination of SiGe HBT's with advanced Si CMOS to form an SiGe BiCMOS technology represents a unique opportunity for Si-based RF system-on-a-chip solutions. This paper reviews state-of-the-art SiGe HBT technology and assesses its potential for current and future RF and microwave systems.

SiGe HBT technology: a new contender for Si-based RF and microwave circuit applications

Fundamental processes in Si/Si and Ge/Si epitaxy studied by scanning tunneling microscopy during growth

In this paper, design aspects of high-speed digital and analog IC's are discussed which allow the designer to exhaust the high-speed potential of advanced Si-bipolar technologies. Starting from the most promising circuit concepts and an adequate resistance level, the dimensions of the individual transistors in the IC's must be optimized very carefully using advanced transistor models. It is shown how the bond inductances can be favourably used to improve circuit performance and how the critical on-chip wiring must be taken into account. Moreover, special modeling aspects and ringing problems, caused by emitter followers, are discussed. An inexpensive mounting technique is presented which proved to be well suited up to 50 Gb/s, the highest data rate ever achieved in any IC technology. The suitability of the design aspects discussed is confirmed by measurements of digital circuits and broadband amplifiers developed for 10 and 40 Gb/s optical-fiber links.

Design considerations for very-high-speed Si-bipolar IC's operating up to 50 Gb/s

Double-mesa type SiGe heterojunction bipolar transistors (HBTs) have been improved by increasing the base Gummel number and by using a thin, highly doped launcher layer between the base and the collector. In addition, the contact resistance of the base contact has been reduced. Hence, it was possible to obtain a record maximum frequency of oscillation up to 160 GHz for a 2-emitter finger HBT in common emitter configuration.

Enhanced SiGe heterojunction bipolar transistors with 160 GHz-f/sub max/

Silicon-germanium heterojunction bipolar transistors (HBTs) have been developed with regard to high cutoff frequencies within a wide collector current range. Unity current gain frequencies f/sub T/ high as 116 GHz were obtained at a collector current density of 2*10/sup 5/ A/cm/sup 2/. In addition, the FWHM of cutoff frequency f/sub T/ against collector current exceeds one and a half decades. Calculations indicate that the ratio of the collector to emitter area essentially determines the current density range of a high frequency HBT. >

SiGe-HBTs with high fT at moderate current densities

SiGe power heterojunction bipolar transistors (HBTs) with 10 and 60/spl times/2.25/spl times/15 /spl mu/m/sup 2/ emitter fingers, respectively, were fabricated in a completely passivated manner by a production-like process. Each emitter stripe of the big transistors includes a ballast resistance of 6 /spl Omega/. Class A load pull measurements at 1.9 GHz revealed a power-added efficiency (PAE) of 44% at 1-W RF output power for the 60-stripes transistor. In addition, a ten-finger driver HBT reached a PAE of 72% at 0.9 GHz for class A/B operation.

1-W SiGe power HBTs for mobile communication

Silicon circuits, now penetrating well into the microwave frequency range, use lossy silicon substrates. Consequently, the microwave performance of transmission lines on this substrate becomes increasingly important and has been investigated here up to 20 GHz. It is shown that transmission lines on 20-/spl Omega//spl middot/cm substrates have no need for backside metallization and backside via holes. Two models for different line types are derived from measurements and verified against them. A coplanar waveguide (CPW) with an overall width of less than 30 /spl mu/m was fabricated with an attenuation of 0.5 dB/mm at 20 GHz, which is acceptable for monolithic microwave integrated circuit (MMIC) design.

Investigation of microstrip and coplanar transmission lines on lossy silicon substrates without backside metallization

SiGe-HBTs have the potential for outstanding analog and digital or mixed-signal high frequency circuits widely based on standard Si technology. Here we review on MBE grown transistors and circuits. Processes and results of a research-like SiGe HBT and two possible production relevant HBT versions are presented. The high frequency results with fmax and fT up to 120 GHz and a minimum noise figure of 0.9 dB at 10 GHz demonstrate the advantage of using MBE samples with steep and high base doping and high germanium contents. A comparison to the concept of reported low doped, low germanium and triangular profiled SiGe base layers, realized by UHV-CVD, is given. In addition, some circuit demonstrators of SiGe-ICs will be presented.

A. Schuppen

Papers

Enhanced SiGe heterojunction bipolar transistors with 160 GHz-f/sub max/

SiGe-HBTs with high fT at moderate current densities

1-W SiGe power HBTs for mobile communication

Investigation of microstrip and coplanar transmission lines on lossy silicon substrates without backside metallization

Mesa and planar SiGe-HBTs on MBE-wafers