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 the highest frequency performance of any solid-state monolithic microwave integrated circuit (MMIC) amplifier. A 2-stage 80-nm gate length InGaAs/InAlAs/InP HEMT MMIC balanced amplifier has a measured on-wafer peak gain of 7.2 dB at 190 GHz and greater than 5 dB gain from 170 to 194 GHz. The circuit was fabricated using a pseudomorphic 20-nm In/sub 0.65/Ga/sub 0.35/As channel HEMT structure grown on a 3-in InP substrate by MBE. Based on the measured circuit results, the intrinsic exhibits an F/sub max/ greater than 400 GHz.

An InP HEMT MMIC LNA with 7.2-dB gain at 190 GHz

We present the TRW 0.1 /spl mu/m InP HEMT MMIC production technology that has been developed and used for state-of-the-art cryogenic LNA applications. The 0.1 /spl mu/m InP HEMT devices typically show cutoff frequency above 200 GHz and transconductance above 1000 mS/mm. Aspects of device design and fabrication are presented which impact important parameters including the InP HEMT device gain, gate leakage current, and parasitic capacitance. One example of state-of-the-art cryogenic MMIC performance is a W-band cryogenic MMIC LNA operated at 20 degrees Kelvin that shows above 23 dB gain and a noise temperature of 30 to 40 K (0.45 to 0.6 dB noise figure) over the band of 80-105 GHz.

0.1 /spl mu/m InP HEMT devices and MMICs for cryogenic low noise amplifiers from X-band to W-band

This paper presents the design, fabrication, and test results of a three-stage 155-GHz monolithic low-noise amplifier (LNA) fabricated with the 0.1-/spl mu/m pseudomorphic (PM) InAlAs-InGaAs-InP HEMT technology. With this amplifier in a test fixture, a small-signal gain of 12 dB was measured at 155 GHz, and more than 10-dB gain from 151 to 156 GHz. When the amplifier was biased for a low noise figure (NF), an NF of 5.1 dB with an associated gain of 10.1 dB was achieved at 155 GHz. All the results above are referred to the monolithic millimetre-wave integrated circuit (MIMIC) chip with the input and output waveguide-to-microstrip line transition losses corrected.

A 155-GHz monolithic low-noise amplifier

A W-band MMIC low-noise amplifier (LNA) was designed and fabricated using NGST's 35nm InP HEMT process. It was packaged in a WR-12 module and tested at 297K and 17.5K ambient temperatures. At room temperature, the WR-12 LNA module has 26–30 dB gain from 70 to 92 GHz and less than 300K noise temperature from 65–86 GHz. At 17.5K ambient temperature, the WR-12 LNA module has a minimum noise temperature of 22K at 85 GHz and less than 40K noise temperature from 70–96 GHz (below 30K noise temperature from 78–95 GHz). Gain at 17.5K is 27–31 dB from 70 to 94 GHz. Power dissipation cold is 2.1 mW. Analysis is also included to investigate the observed frequency shift with ambient temperature. It is believed that these are the lowest noise temperature measured for a packaged W-band amplifier at both room and cryogenic temperatures.

A W-band low-noise amplifier with 22K noise temperature

We present the development of a low noise amplifier (LNA) module which demonstrates gain >24 dB and noise figure (NF)<5.5 dB at 183 GHz. Our previous results reported NF<8.3 dB [1], This improvement was achieved by inserting a single-ended microwave monolithic integrated circuit (MMIC) LNA utilizing TRW's 0.08 /spl mu/m gate InP MMIC technology. This paper discusses the development of the new MMIC LNA, reviews the previous results and presents the new data that was obtained,.

Richard Lai

Papers

An InP HEMT MMIC LNA with 7.2-dB gain at 190 GHz

0.1 /spl mu/m InP HEMT devices and MMICs for cryogenic low noise amplifiers from X-band to W-band

A 155-GHz monolithic low-noise amplifier

A W-band low-noise amplifier with 22K noise temperature

A 183 GHz low noise amplifier module with 5.5 dB noise figure for the conical-scanning microwave imager sounder (CMIS) program