Joel Schleeh

Ultralow-Power Cryogenic InP HEMT With Minimum Noise Temperature of 1 K at 6 GHz

We present in this letter an InGaAs/InAlAs/InP high-electron-mobility transistor (InP HEMT) with record noise temperature at very low dc power dissipation. By minimizing parasitic contact and sheet resistances and the gate current, a 130-nm-gate-length InP HEMT was optimized for cryogenic low-noise operation. When integrated in a 4- to 8-GHz three-stage hybrid low-noise amplifier operating at 10 K, a noise temperature of 1.2 K ± 1.3 K at 5.2 GHz was measured. The gain of the amplifier across the entire band was 44 dB, consuming only 4.2 mW of dc power. The extracted minimum noise temperature of the InP HEMT was 1 K at 6 GHz.

Characterization and Modeling of Cryogenic Ultralow-Noise InP HEMTs

Detailed S-parameter and noise characterization and modeling of ultralow-noise InP/InAlAs/InGaAs high-electron mobility transistors (InP HEMTs) optimized for operation at 10 K are presented. At the optimum low-noise bias at 10 K, the InP HEMT exhibited a 60% improvement in cutoff frequency fT and a 100% improvement in dc transconductance gm compared with 300 K. A small-signal noise model was evaluated at different bias conditions at 10 and 300 K. The bias dependence of the minimum noise temperature at low-noise operation was modeled at 10 K. The temperature dependence of the threshold voltage VT, gm, and gate-source and gate-drain capacitances Cgs and Cgd indicated that the excellent cryogenic noise performance of optimized InP HEMTs is due to a higher degree of confinement in the carrier concentration closest to the gate at 10 K compared with 300 K. As a result, a fast depletion of the HEMT channel with respect to drain current Id occurs under cryogenic operation.

Phonon black-body radiation limit for heat dissipation in electronics

Thermal dissipation at the active region of electronic devices is a fundamental process of considerable importance. Inadequate heat dissipation can lead to prohibitively large temperature rises that degrade performance, and intensive efforts are under way to mitigate this self-heating. At room temperature, thermal resistance is due to scattering, often by defects and interfaces in the active region, that impedes the transport of phonons. Here, we demonstrate that heat dissipation in widely used cryogenic electronic devices instead occurs by phonon black-body radiation with the complete absence of scattering, leading to large self-heating at cryogenic temperatures and setting a key limit on the noise floor. Our result has important implications for the many fields that require ultralow-noise electronic devices.

Cryogenic Performance of Low-Noise InP HEMTs: A Monte Carlo Study

In this paper, we present a study of the cryogenic performance of InP high electron mobility transistors (HEMTs) in the low-noise region by means of Monte Carlo simulations. A decrease of the contact resistances and an increase in the electron velocity in the channel together with enhanced channel electron confinement upon cooling of the device are observed, and considered to be the reason for the excellent low-noise behavior of cryogenic InP HEMTs. These findings are supported by a good agreement between simulated and experimental DC, RF, and noise figure data of a 130-nm gate length InP HEMT at 300 and 77 K. An increase of the transconductance gm and gate-to-source capacitance Cgs is observed when cooling from 300 to 77 K as a consequence of electron velocity increase and improved channel confinement.

Cryogenic Kink Effect in InP pHEMTs: A Pulsed Measurements Study

We present a study based on pulsed measurement results of the kink effect observed on the I-V output characteristics in InGaAs/InAlAs/InP pseudomorphic high-electron mobility transistors (InP pHEMTs) at cryogenic temperatures. Pulsed measurements were performed at 300 and 10 K. Gate and drain lags were observed at both temperatures with a strong increase upon cooling for the drain lag. To study the influence of surface traps in the kink, pulsed measurements of devices passivated by either atomic layer deposited Al2O3 or plasma enhanced chemical vapor deposited Si3N4 were compared with no significant differences at 10 K. The influence on the kink effect from the buffer was studied by comparing pulsed measurement data from an InP pHEMT with measurements on a GaAs metamorphic HEMT (GaAs mHEMT). For the GaAs mHEMT, an increase of the drain lag at 10 K was observed when compared with the InP pHEMT. Contrary to the InP HEMT, for the GaAs mHEMT the 0.1 μs pulses were short enough to eliminate the kink when using a quiescent point with VDS = 0. The quality of the pinchoff was sensitive to pulse length and quiescent point for the InP pHEMT but not for the GaAs mHEMT.

Cryogenic ultra-low noise amplification - InP PHEMT vs. GaAs MHEMT

We present a comparative study of 130 nm high electron mobility transistors (HEMTs) fabricated on pseudomorphic InGaAs/InAlAs/InP (InP PHEMT) and InGaAs/InAlAs/GaAs (GaAs MHEMT) intended for ultra-low noise amplifiers (LNAs). The epitaxial growth, as well as the HEMT process, was performed simultaneously. When integrated in a 4-8 GHz 3-stage LNA at 300 K, the measured average noise temperature was 34 K for the GaAs MHEMT and 27 K for the InP PHEMT. When cooled down to 10 K, the InP PHEMT LNA was improved to 1.6 K, while the GaAs MHEMT LNA was only reduced to 5 K. The reason for the superior cryogenic noise performance of the InP PHEMT compared to the GaAs MHEMT in this study, was found to be a higher quality of pinch-off when cooled down.

Cryogenic 0.5–13 GHz low noise amplifier with 3 K mid-band noise temperature

A 0.5–13 GHz cryogenic MMIC low-noise amplifier (LNA) was designed and fabricated using a 130 nm InP HEMT process. A packaged LNA has been measured at both 300 K and 15 K. At 300 K the measured minimum noise temperature was 48 K at 7 GHz. At 15 K the measured minimum noise temperature was 3 K at 7 GHz and below 7 K within the entire 0.5–13 GHz band. The gain was between 34 dB and 40 dB at 300 K and between 38 dB and 44 dB at 4 K.

Cryogenic W-band LNA for ALMA band 2+3 with average noise temperature of 24 K

A cryogenic low noise amplifier that operates across the E and W-bands, from 65 GHz to 116 GHz, has been developed using 0.1-μm InP HEMT technology. Such wideband performance makes this work suitable for the ALMA telescope where two of its bands, 67–90 GHz of Band 2 and 85–116 GHz of Band 3, can be combined into one. At an ambient temperature of 5.5 K, this W-band LNA demonstrates an average noise temperature of 24.7 K with more than 21 dB gain and +/−3.0 dB gain flatness from 65 GHz to 116 GHz. To the best knowledge of the authors, this combination of bandwidth, gain flatness and noise temperature has not been demonstrated before.

10 K room temperature LNA for SKA band 1

A room temperature LNA suitable for Square Kilometer Array band 1 (0.35-1.05 GHz) has been designed, fabricated and tested. The design is based on InP HEMTs, and focused on minimizing losses in the input matching network. Noise measurement methods in two different labs were used to confirm the 10 K noise temperature of the LNA. The gain was flat at 50 dB and the input and output return loss better than 10 dB in most of the band.

Cryogenic low-noise InP HEMTs: A source-drain distance study

The scaling effect of the source-drain distance was investigated in order to improve the performance of low-noise InP HEMTs at cryogenic temperatures 4-15 K. The highest dc transconductance at an operating temperature of 4.8 K and low bias power was achieved at a source-drain distance of 1.4 μm. The extracted HEMT minimum noise temperature was 0.9 K at 5.8 GHz for a 3-stage 4-8 GHz hybrid low-noise amplifier at 10 K.