Anders Mellberg

Cryogenic wide-band ultra-low-noise IF amplifiers operating at ultra-low DC power

This paper describes cryogenic broad-band amplifiers with very low power consumption and very low noise for the 4-8-GHz frequency range. At room temperature, the two-stage InP-based amplifier has a gain of 27 dB and a noise temperature of 31 K with a power consumption of 14.4 mW per stage, including bias circuitry. When cooled to 15 K, an input noise temperature of 1.4 K is obtained at 5.7 mW per stage. At 0.51 mW per stage, the input noise increases to 2.4 K. The noise measurements have been repeated at different laboratories using different methods and are found consistent.

An evaluation of three simple scalable MIM capacitor models

This paper presents an evaluation of three different scalable metal-insulator-metal capacitor models for use in monolithic-microwave integrated-circuit design. The models, including one previously unpublished, are based on transmission-line theory and are easily scalable using only physical dimensions and constants. Comparisons to measured data for several device sizes, up to 45deg in electrical length, show that the three models exhibit similar performance, with a mean deviation between models and S11 measurements that is less than 3%

Fabrication and characterization of reactively sputtered TaN thin-film resistors for millimeter wave applications

A tantalum nitride (TaN) thin-film resistor (TFR) lift-off process was developed by reactively sputtering TaN from a pure Ta metal target. The films were deposited at a rate of approximately 3 A/s using a N 2 /Ar ratio of 0.22 at 5 mTorr and 100 W of de power. TFRs were fabricated on silicon and semi-insulating InP with reproducible resistances of 80-85 Ω/□ at thicknesses of 550-700 A using a lift-off technique. Resistors fabricated on semi-insulating InP utilizing microstrip technology were characterized by S-parameter measurements up to 67 GHz. A model, based on a lossy transmission line, described the TFRs with good accuracy.

Cryogenic 2-4 GHz ultra low noise amplifier

This paper describes two-stage InP-based cryogenic broadband amplifier with very low noise for the frequency band 1.5-4.5 GHz. For a band of 2-4 GHz at 15 K the measured gain is 30.0/spl plusmn/2 dB and a noise temperature below 5 K. The total DC power consumption of the amplifier is 6.8 mW.

InP HEMT-based, cryogenic, wideband LNAs for 4-8 GHz operating at very low DC-power

We present cryogenic broadband amplifiers for 4-8 GHz with very low dc-power consumption and low noise. Two different amplifiers were designed and manufactured, one of which was based on in-house InP devices and the other on commercial GaAs devices. When cooled to 15 K, the InP-based amplifier shows an input noise temperature of 3.9 K at a dc-power consumption of 3.7 mW. The GaAs-based amplifier shows an input noise temperature of 6.5 K at a dc-power consumption of 23 mW.

InGaAs-InAlAs-InP HEMT technology for ultra-high frequency and ultra-low noise performance

InGaAs-InAlAs-InP HEMT is facing competition from the emerging MHEMT technology. Nonetheless, for top-performing applications requiring high gain and low noise, InP HEMT is still the preferred choice. We here present results from InP HEMT development for sub-100 nm gate length designs yielding f/sub max/ above 400 GHz and ultra-low noise hybrid amplifiers with a minimum noise temperature of 1.1 K when operated under cryogenic conditions.

Vertical scaling of gate-to-channel distance for a 70 nm InP pseudomorphic HEMT technology

DC and HF performance for a 70 nm InP PHEMT technology have been studied as a function of gate-to-channel distance. The optimized PHEMT exhibited a maximum transconductance of 1.5 S/mm and f/sub max/ of 400 GHz.

A novel gate process for InP based HEMTs with gate length from 0.06 to 0.2 /spl mu/m

A novel, fast and reliable process for making T-shaped gates has been developed. It uses two PMMA layers and one PMGI resist layer which have completely selective developers that result in a large process window. Using this process scheme, gate lengths from 60 to 200 nm have easily been made in the same process step. The processed InP-HEMTs show excellent dc and rf-performance. The process has a good control of the gate lengths and give a high yield, and is therefore suitable for mass production of HEMTs and MMICs.