Nathalie Rolland

A 60 GHz Power Amplifier With 14.5 dBm Saturation Power and 25% Peak PAE in CMOS 65 nm SOI

A 60 GHz wideband power amplifier (PA) is fabricated in a standard CMOS SOI 65 nm process. The PA is based on two cascode stages. Input, output and inter-stage matching use coplanar wave guide (CPW) transmission lines that have low losses thanks to the high-resistivity SOI substrate (3 kΩ · cm). The PA measurements are carried out for supply voltages VDD going from 1.2 V to 2.6 V and achieve a saturation power of 10 dBm to 16.5 dBm respectively. The peak power-added efficiency (PAE) is higher than 20% for all applied VDD values.

Packaging methodology for RF devices using a BCB membrane transfer technique

This paper presents a whole benzocyclobutene (BCB) film encapsulated 0-level packaging using a wafer level BCB bonding technique. The wafer-scale membrane transfer technique using silicon carrier wafers was used to make BCB membrane caps for encapsulation placed above the device wafers. The BCB multiple coating process using CYCLOTENE 4026-46 was developed to make an encapsulation cap. The average height of the BCB cap was 40 µm with a little curvature on the membrane for the dimension of 2 mm × 3 mm. The RF characteristics using coplanar waveguide (CPW) lines were measured to evaluate the effect of BCB film packaging and the results were compared with those of pyrex #7740 glass packaged CPW lines. It shows that the insertion loss (S12) of BCB-packaged CPW lines is better than that of pyrex glass packaged CPW lines at high frequencies. The insertion loss change of CPW lines by BCB film packaging is below 0.01 dB up to 90 GHz, while the glass-packaged CPW lines show about 0.1 dB deviation from 20 GHz to 110 GHz.

UWB in Millimeter Wave Band With Pulsed ILO

A simple but efficient transmitter for ultra-wide-band impulse radio wavelet generator in millimeter-wave band is presented. It is suitable for RADAR, gigabit wireless personal area network, and localization applications. This front-end involves a subharmonic injection-locked oscillator driven by a pulse generator (PG) with fast transition time (<25 ps). Its frequency oscillation is locked on one of the numerous harmonic components generated by the PG around 30 GHz. This allows to obtain a stable pulse-to-pulse phase condition and a very low phase noise (<-110 dBc/Hz@100 kHz). Two monolithic microwave integrated circuits have been designed using a commercial pseudomorphic high-electron mobility transistor foundry process (ft = 100 GHz). The first one is a PG with position and width modulation capabilities, and the second one is an oscillator with a 30-GHz free-running output frequency. The start of the oscillations is studied, using the external quality factor as main factor.

First Demonstration of High-Power GaN-on-Silicon Transistors at 40 GHz

In this letter, high-output-power-density GaN-based high-electron-mobility transistors grown on a 100-mm silicon substrate is demonstrated for the first time at 40 GHz. The use of an optimized double heterostructure based on ultrathin barrier AlN/GaN allows both high current density and low leakage current, resulting in high-frequency performance (fmax close to 200 GHz). Furthermore, the control of the trapping effects on these highly scaled devices enabled to set a first benchmark at 40 GHz with 2.5 W/mm at VDS = 15 V, mainly limited by RF losses and thermal issues. These results show that an AlN/GaN/AlGaN heterostructure grown on silicon substrate is a viable technology for cost-effective high-power millimeter-wave amplifiers fully compatible with standard Si-based devices.

Design, Fabrication, and Measurement of Benzocyclobutene Polymer Zero-Level Packaging for Millimeter-Wave Applications

This paper presents a whole benzocyclobutene (BCB) membrane zero-level packaging using a wafer-level BCB bonding technique and a membrane transfer technique with silicon carrier wafers for millimeter-wave devices. The developed packaging technology has been applied to a coplanar line and thin-film planar resonator to evaluate the effect of the packaging on their RF performance. The packaged coplanar line has shown an insertion loss change less than 0.01 dB/mm from dc to 110 GHz and thin-film resonator has 0.6-dB return loss change at 62.5-GHz resonant frequency after packaging. In addition, a flip-chip compatible BCB packaging technology has been implemented using gold-electroplating technology for a vertical interconnection. The effects of a vertical interconnection on the coplanar line and a BCB layer over the gold-plugged coplanar line have also been investigated

Transposition of a baseband UWB signal at 60 GHz for high data rate indoor WLAN

The purpose of this letter is to demonstrate the high potentiality in terms of data rate and multiple access of a novel 60-GHz WLAN architecture for smart objects and indoor communication systems. This approach is based on the up-conversion of an ultrawide-bandwidth impulse radio signal (IR-UWB) in the 60-GHz frequency range to benefit of the natural advantages of the UWB technique while avoiding the baseband limitations. First results about the pulse generator and receiver architecture are discussed.

High-Performance Low-Leakage-Current AlN/GaN HEMTs Grown on Silicon Substrate

In this letter, ultrathin-barrier AlN/GaN high-electron mobility transistors (HEMTs) capped with in situ metal-organic-chemical-vapor-deposition-grown SiN have been successfully fabricated on 100-mm Si substrates. Output current density exceeding 2 A/mm has been reached, which represents, to the best of our knowledge, the highest value ever achieved for GaN-on-Si HEMTs. This results from the high 2DEG density of the optimized AlN/GaN heterostructure. Despite the ultrathin barrier of 6 nm, low gate and drain leakage currents of about 10 μA/mm are obtained without the use of a gate dielectric that generally induces reliability issues. Furthermore, the high aspect ratio (gate length Lg/gate-to-channel distance) and low RF losses (at the buffer/Si substrate interface) are reflected in excellent RF performances. The current gain extrinsic cutoff frequency fT and the maximum oscillation frequency fmax were 52 and 102 GHz with a 0.2- μm gate length, respectively, resulting in an fT·Lg product as high as the reported state-of-the-art GaN-on-Si HEMTs.

Demonstration of low leakage current and high polarization in ultrathin AlN/GaN high electron mobility transistors grown on silicon substrate

High quality AlN/GaN heterostructures grown on silicon substrate are demonstrated. It is found that high carrier concentration can be achieved whereas circular diodes showed a low leakage current up to 200 V reverse bias. 200 nm gate length AlN/GaN transistors exhibited a drain current density of 1.3 A/mm with a pinchoff leakage current below 20 μA/mm and a record GaN-on-silicon extrinsic transconductance of 470 mS/mm. These results demonstrate the possibility to achieve a unique combination of large polarization with a barrier thickness as low as 3 nm while preserving a remarkably low device leakage current without using any gate insulator.

A 60 GHz UWB impulse radio transmitter with integrated antenna in CMOS65nm SOI technology

This work describes an UWB impulse transmitter with integrated antenna in the 60 GHz band implemented in CMOS65nm SOI technology. The transmitter aims low-power short-range high data-rate communication systems for fast-downloading applications. It consists of an oscillator that is switched on-and-off by the digital data to be transmitted and a medium power amplifier. The transmitter is fabricated on two chips: one for direct on-chip measurements and another one implementing an integrated antenna. The transmitter measurements are performed on-chip and in free space in both continuous wave and impulse operating modes. The circuit achieves an equivalent isotropic radiated power of 2 dBm at 56 GHz and a maximum measured data rate of 2.222 Gbit/sec. The overall power consumption is 28 mW under 1.2 V voltage supply.

Effects of AlGaN Back Barrier on AlN/GaN-on-Silicon High-Electron-Mobility Transistors

In this work, the effects of an AlGaN back barrier in the dc and RF performances of AlN/GaN high-electron-mobility transistors (HEMTs) grown on 100 mm Si substrates have been investigated. It is shown that the outstanding dc performance in highly scaled AlN/GaN-on-Si HEMTs can be fully preserved when introducing an AlGaN back barrier while significantly reducing the sub-threshold drain leakage current and enhancing the RF performance by the reduction of short-channel effects. Therefore, the AlN/GaN/AlGaN double heterostructure enables high-aspect-ratio devices generating extremely high current density, low leakage current, and high voltage operation.