Photo/EB hybrid exposure process for T-shaped gate superlow-noise HEMTs

GaAs IC Symposium IEEE Gallium Arsenide Integrated Circuit Symposium 17th Annual Technical Digest 1995

et al.

Self Cite

A Q-band high gain and low noise Variable Gain Amplifier (VGA) using dual gate AlGaAdInGaAs pseudomorphic HEMTs has been developed. The dual gate HEMT can be fabricated using the same process as the single gate HEMT which a gate length of 0.15 pm. The Q-band VGA consists of a 1-stage low noise amplifier MMIC using a single gate HEMT and a 2-stage VGA MMIC using dual gate HEMTs. The VGA has a gain of more than 20 dB from 41 GHz to 52 GHz. A gain control range of more than 30 dB is obtained in the same frequency range. A minimum noise figure of 1.8 dB with an associated gain of 22 dB is achieved at 43 GHz when biased for a low noise figure. This performance is comparable with the best data ever reported for LNAs at Q-band including both GaAs based HEMTs and InP based HEMTs.

Section: Device and Mmic Fabricationmentioning

confidence: 99%

A Q-band high gain and low noise variable gain amplifier using dual gate HEMTs

Kashiwa

Komaru

GaAs IC Symposium IEEE Gallium Arsenide Integrated Circuit Symposium 17th Annual Technical Digest 1995

et al.

Self Cite

“…The gate length and width are 0.2 and 80 m, respectively. The gate electrode is defined by a photo/electron beam (EB) hybrid exposure system with double-layer resist layers [14]. This process has excellent wafer throughput because it utilizes a step-and-repeat exposure procedure instead of EB lithography in fabricating the wide head of the T-shaped gate structure.…”

mentioning

confidence: 99%

V-band high-power low phase-noise monolithic oscillators and investigation of low phase-noise performance high drain bias

Kashiwa

Ishida

IEEE Trans. Microwave Theory Techn.

et al. 1998

Self Cite

This paper reports on the excellent performance of V -band monolithic high electron-mobility transistor (HEMT) oscillators, and discusses oscillation characteristics on drain bias. With regard to output characteristics, double-hetero (DH) HEMT (especially with a high-density Si-planar doped layer) are superior to single-hetero (SH) HEMT's. A monolithic microwave integrated circuit (MMIC) oscillator has been developed with a planar doped DH HEMT and has achieved the peak output power of 11.1 dBm at a 55.9-GHz oscillation frequency. Phase noise of 085 dBc/Hz at 100-kHz offset and 0103 dBc/Hz at 1-MHz offset have been achieved at a drain voltage of 5.5 V and a gate voltage of 0 V. These characteristics have been achieved without any buffer amplifiers or dielectric resonators. This study has revealed that the phase noise decreases as drain voltage increases. This phenomenon is caused by lower pushing figure and lower noise level at a low-frequency range obtained under a high drain voltage. It is because the depletion layer in the channel is extendedto the drain electrode with increase of drain voltage, resulting in the small fluctuation of the gate-to-source capacitance. We also investigate low-frequency noise spectra of AlGaAs/InGaAs/GaAs DH HEMT's with different bias conditions. The low-frequency noise decreases for more than 3 V of the drain voltage. A unique mechanism is proposed to explain this phase noise reduction at high drain voltage.

“…In delineating the T-shaped gate electrode, a double layer resist process has been adopted [4]. The gate length was 0.1.5pm.…”

Section: Processmentioning

confidence: 99%

A 60 GHz-band ultra low noise planar-doped HEMT

1993 IEEE MTT-S International Microwave Symposium Digest

Yoshida

Matsuda

et al.

Self Cite

An ultra low noise AlGaAsbnGaAs HEMT with a 0.15pm T-shaped gate and Si planer-doped layer has been developed for millimeter-wave systems. The HEMT showed the extremely reduced minimum noise figure of 1.6dB and high associated gain of 6.5dB at 6OGHz. The noise figure is the lowest value ever reported for the AlGaAsDnGaAs pseudomorphic HEMT. INTRODUCTIONRecent developments in heterostructure transistor technology have advanced very rapidly outstanding low-noise amplification results throughout the microwave and millimeter-wave frequency range 11-31. Applications requiring low-noise, high-gain performance such as radar, communication, remote _.