Mehran Matloubian

112-GHz, 157-GHz, and 180-GHz InP HEMT traveling-wave amplifiers

We report traveling-wave amplifiers having 1-112 GHz bandwidth with 7 dB gain, and 1-157 GHz bandwidth with 5 dB gain. A third amplifier exhibited 5 dB gain and a 180 GHz high-frequency cutoff. The amplifiers were fabricated in a 0.1-/spl mu/m gate length InGaAs/InAlAs HEMT MIMIC technology. The use of gate-line capacitive-division, cascode gain cells and low-loss elevated coplanar waveguide lines have yielded record bandwidth broad-band amplifiers.

650-AA self-aligned-gate pseudomorphic Al/sub 0.48/In/sub 0.52/As/Ga/sub 0.2/In/sub 0.8/As high electron mobility transistors

The authors report on the design and fabrication of a 650-AA self-aligned-gate pseudomorphic Al/sub 0.48/In/sub 0.52/As/Ga/sub 0.2/In/sub 0.8/As high electron mobility transistor (HEMT) with a state-of-the-art current gain cutoff frequency of over 300 GHz. This work clearly demonstrates the potential of sub-0.1- mu m gate-length HEMTs for near-future microwave and millimeter-wave applications.<<ETX>>

155- and 213-GHz AlInAs/GaInAs/InP HEMT MMIC oscillators

We report on the design and measurement of monolithic 155- and 213-GHz quasi-optical oscillators using AlInAs/GaInAs/InP HEMTs. These results are believed to be the highest frequency three-terminal oscillators reported to date. The indium concentration in the channel was 80% for high sheet charge and mobility. The HEMT gates were fabricated with self-aligned sub-tenth-micrometer electron-beam techniques to achieve gate lengths on the order of 50 nm and drain-source spacing of 0.25 /spl mu/m. Planar antennas were integrated into the fabrication process resulting in a compact and efficient quasioptical Monolithic Millimeter-wave Integrated Circuit (MMIC) oscillator. >

A measurement-based design equation for the attenuation of MMIC-compatible coplanar waveguides

Measured attenuation of coplanar waveguide (CPW) transmission lines with narrow strip and slot widths fabricated on GaAs, high-resistivity Si, and InP is used to derive a new closed form equation to calculate line losses. This new equation is shown to be more accurate than previous expressions, yet simple enough to be programmed into a hand-held calculator since it is based on a simple relationship between attenuation and the product of the strip and slot widths. The derived equation is applicable to CPWs with aspect ratio and metal thicknesses commonly used in monolithic microwave integrated circuits.

V-band high-efficiency high-power AlInAs/GaInAs/InP HEMT's

The authors report on the state-of-the-art power performance of InP-based HEMTs (high electron mobility transistors) at 59 GHz. Using a 448- mu m-wide HEMT with a gate length of 0.15 mu m, an output power of 155 mW with a 4.9-dB gain and a power-added efficiency of 30.1% were obtained. By power-combining two of these HEMTs, an output power of 288 mW with 3.6-dB gain and a power-added efficiency of 20.4% were achieved. This is the highest output power reported with such a high efficiency for InP-based HEMTs, and is comparable to the best results reported for AlGaAs/InGaAs on GaAs pseudomorphic HEMTs at this frequency. >

High-power V-band AlInAs/GaInAs on InP HEMTs

The DC and RF performance of delta -doped channel AlInAs/GaInAs on InP power high-electron-mobility transistors (HEMTs) are reported. A 450- mu m-wide device with a gate-length of 0.22 mu m has achieved an output power of 150 mW (at the 1-dB gain compression point) with power-added efficiency of 20% at 57 GHz. The device has a saturated output power of 200 mW with power-added efficiency of 17%. This is the highest output power measured from a single InP-based HEMT at this frequency, and demonstrates the feasibility of these HEMTs for high-power applications in addition to low-noise applications at V-band.<<ETX>>

Effects of channel quantization and temperature on off-state and on-state breakdown in composite channel and conventional InP-based HEMTs

On- and off- state breakdown effects in composite channel and conventional InP-based HEMTs are studied by means of electrical measurements, and electroluminescence spectroscopy. We demonstrate that channel quantization increases off-state and on-state breakdown voltage. The temperature coefficient of the electron impact ionization rate in In/sub 0.53/Ga/sub 0.47/As has been studied. Differently from what happens in GaAs-based devices, carrier multiplication increases on increasing the temperature.

High power and high efficiency AlInAs/GaInAs on InP HEMTs

The authors report on the development of AlInAs/GaInAs-on-InP power HEMTs (high electron mobility transistors). Output power densities of more than 730 mW/mm and 960 mW/mm with power-added efficiencies (PAE) of 50% and 40% respectively, were achieved at 12 GHz. When biased for maximum efficiency, a PAE of 59% and an output power of 470 mW/mm with 11.3 dB gain were obtained. These results demonstrate the viability of these HEMTs for power amplification. Considering that these HEMTs have an f/sub max/ of over 200 GHz, they should also have good power performance at millimeter-wave frequencies.<<ETX>>

High-performance submicrometer gatelength GaInAs/InP composite channel HEMT's with regrown ohmic contacts

This letter reports DC and RF performance of 0.25 /spl mu/m gatelength GaInAs/InP composite channel HEMTs with nonalloyed, regrown ohmic contacts by MOCVD. Regrown channel contacts are used to achieve low contact resistance (0.35 /spl Omega/-mm) to (50 /spl Aring/) GaInAs/(150 /spl Aring/) InP composite channel HEMTs. High transconductance (600 mS/mm), high full channel current (650 mA/mm), and high peak cut-off frequencies (F/sub t/=70 GHz, F/sub max/=170 GHz) are observed. Contact transfer resistance of regrown channel contacts is compared to conventional alloyed contacts for varying GaInAs/InP channel composition.

InP-based HEMT's with Al/sub 0.48/In/sub 0.52/As/sub x/P/sub 1-x/ Schottky layers

In this letter we report on the DC and RF performance of InP-based HEMTs with Al/sub 0.48/In/sub 0.52/As/sub x/P/sub 1-x/ Schottky layers and GaInAs/InP composite channels. By replacing the Al/sub 0.48/In/sub 0.52/As Schottky layer with Al/sub 0.48/In/sub 0.52/As/sub x/P/sub 1-x/ we have been able to increase the bandgap of the Schottky layer and achieve record breakdown voltages for 0.15 /spl mu/m gate-length InP-based HEMTs. The 0.15 /spl mu/m gate-length HEMTs have gate-to-drain breakdown voltages of over 13 V with current densities of 620 mA/mm and maximum transconductances of 730 mS/mm. On a wafer with a higher sheet charge we have obtained gate-to-drain breakdown voltages of 10.5 V with current densities of over 900 mA/mm. These are the highest breakdown voltages reported for 0.15 /spl mu/m gate-length InP-based HEMTs with such high current densities. At 10 GHz a 450 /spl mu/m wide HEMT has demonstrated 350 mW (780 mW/mm) of output power with power-added efficiency of 60% and 12 dB gain.<<ETX>>