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

The rapid development of the RF power electronics requires the introduction of wide bandgap material due to its potential in high output power density, high operation voltage and high input impedance GaN-based RF power devices have made substantial progresses in the last decade This paper attempts to review the latest developments of the GaN HEMT technologies, including material growth, processing technologies, device epitaxial structures and MMIC designs, to achieve the state-of-the-art microwave and millimeter-wave performance The reliability and manufacturing challenges are also discussed

GaN-Based RF Power Devices and Amplifiers

Recent changes in how people consume multimedia services are causing an explosive increase in mobile traffic. With more and more people using wireless networks, the demand for the ultra-fast wireless communications systems is increasing. To date, this demand has been accommodated with advanced modulation schemes and signal-processing technologies at microwave frequencies. However, without increasing the carrier frequencies for more spectral resources, it may be quite difficult to keep up with the needs of users. Although there are several alternative bands, recent advances in terahertz-wave (THz-wave) technologies have attracted attention due to the huge bandwidth of THz waves and its potential for use in wireless communications. The frequency band of 275 ~ 3000 GHz , which has not been allocated for specific uses yet, is especially of interest for future wireless systems with data rates of 10 Gb/s or higher. Although THz communications is still in a very early stage of development, there have been lots of reports that show its potential. In this review, we will examine the current progress of THz-wave technologies related to communications applications and discuss some issues that need to be considered for the future of THz communications.

Present and Future of Terahertz Communications

Microwave photonics with superconducting quantum circuits

As silicon-based electronics approach the limit of improvements to performance and capacity through dimensional scaling, attention in the semiconductor field has turned to graphene, a single layer of carbon atoms arranged in a honeycomb lattice. Its high mobility of charge carriers (electrons and holes) could lead to its use in the next generation of high-performance devices. Graphene is unlikely to replace silicon completely, however, because of the poor on/off current ratio resulting from its zero bandgap. But it could be used to improve silicon-based devices, in particular in high-speed electronics and optical modulators.

A role for graphene in silicon-based semiconductor devices

We present a unique high performance 0.15 /spl mu/m InGaAs/AlGaAs/GaAs HEMT MMIC power amplifier fabricated with a 2-mil thick GaAs substrate which operates at V-band. The 2-stage 59-64 GHz power MMIC amplifier exhibits 27% peak power added efficiency at 60 GHz with 275 mW output power (350 mW/mm) and 11 dB power gain. When biased for higher output power, 400 mW output power was achieved at 60 GHz with 24.5% power added efficiency. This is the highest reported combination of output power and power added efficiency reported to date at this frequency band. This amplifier also exhibits outstanding wideband power characteristics with 25.5/spl plusmn/0.5 dBm output power measured from 59-64 GHz.

A high efficiency 0.15 /spl mu/m 2-mil thick InGaAs/AlGaAs/GaAs V-band power HEMT MMIC

We present two low-noise amplifiers for the frequency range of 160 to 270 GHz. The amplifiers were fabricated using a 35-nm InP HEMT technology and designed for room temperature and cryogenic operation. A four-stage amplifier in a common-source topology and a three-stage amplifier utilizing a cascode stage at the output achieve 15 to 25-dB on-wafer measured gain from 160 to 270 GHz. When packaged in WR5 waveguide housings the amplifiers exhibit room temperature measured noise of 600 to 760 K from 160 to 220 GHz. When cryogenically cooled the three-stage amplifier shows a noise of 80 to 115 K over the range of 164 to 220 GHz. Furthermore, our initial room temperature measurements show a noise figure of 7-8 dB over the 220 to 252 GHz range for a four-stage amplifier packaged in a WR3 waveguide housing.

160-270-GHz InP HEMT MMIC Low-Noise Amplifiers

We report the performance of a monolithic V-band power amplifier using 0.15-/spl mu/m double heterostructure pseudomorphic InGaAs/AlGaAs/GaAs HEMT's. The amplifier using a 400-/spl mu/m device driving a 2/spl times/400-/spl mu/m device. It has demonstrated output power of 313 mW (0.39 W/mm) with 8.95 dB power gain and 19.9% PAE at 59.5 GHz. These data represent the highest reported combination of output power, power gain, and power-added efficiency reported for a V-band monolithic power amplifier. >

A high efficiency V-band monolithic HEMT power amplifier

A high power broadband monolithic power amplifier operating from 29 to 32 GHz is presented for Ka-band ground terminal applications. Using 0.15 /spl mu/m InGaAs/AlGaAs/GaAs pseudomorphic HEMT (PHEMT) devices, the two stage power amplifier on 4 mil GaAs substrate demonstrated greater than 16 dB small signal gain and 32 dBm (1.6 watts) power. The amplifier attained peak output power of 33 dBm (2 watts) and power added-efficiency of 27%. At this power level, the amplifier exhibited power densities in excess of 620 mW/mm. Performance capabilities of the HEMT power amplifiers at millimeter-wave frequencies is documented in terms of power densities at 1 dB compression and at saturation, as well as power-added efficiency.

A high power broadband monolithic power amplifier for Ka-band ground terminals

A monolithic W-band three-stage low-noise amplifier (LNA) based on 0.1- mu m pseudomorphic (PM) InAlAs/InGaAs/InP high-electron-mobility transistors (HEMTs) has been developed. This LNA has demonstrated a noise figure of 4.3 dB and an associated small-signal gain of 19 dB at 100 GHz with a low DC power consumption of 20 mW. This demonstrates the potential of InP HEMT technology for higher millimeter-wave applications. The gain and noise performance is comparable with the best reported results of the monolithic W-band LNA using GaAs-based PM HEMTs even at this first iteration phase of the development. The HEMTs discussed consume only 30% of the DC power typically needed in the GaAs-based HEMT LNAs with the same device periphery and design approach. >

Richard Lai

Papers

A high efficiency 0.15 /spl mu/m 2-mil thick InGaAs/AlGaAs/GaAs V-band power HEMT MMIC

160-270-GHz InP HEMT MMIC Low-Noise Amplifiers

A high efficiency V-band monolithic HEMT power amplifier

A high power broadband monolithic power amplifier for Ka-band ground terminals

A monolithic W-band three-stage LNA using 0.1 mu m InAlAs/InGaAs/InP HEMT technology