M. Zaknoune

Metamorphic In/sub 0.4/Al/sub 0.6/As/In/sub 0.4/Ga/sub 0.6/As HEMTs on GaAs substrate

New In/sub 0.4/Al/sub 0.6/As/In/sub 0.4/Ga/sub 0.6/As metamorphic (MM) high electron mobility transistors (HEMTs) have been successfully fabricated on GaAs substrate with T-shaped gate lengths varying from 0.1 to 0.25 /spl mu/m. The Schottky characteristics are a forward turn-on voltage of 0.7 V and a gate breakdown voltage of -10.5 V. These new MM-HEMTs exhibit typical drain currents of 600 mA/mm and extrinsic transconductance superior to 720 mS/mm. An extrinsic current cutoff frequency f/sub T/ of 195 GHz is achieved with the 0.1-/spl mu/m gate length device. These results are the first reported for In/sub 0.4/Al/sub 0.6/As/In/sub 0.4/Ga/sub 0.6/As MM-HEMTs on GaAs substrate.

InAlAs/InGaAs Metamorphic High Electron Mobility Transistors on GaAs Substrate: Influence of Indium Content on Material Properties and Device Performance

The development of lattice mismatched InAlAs/InGaAs high electron mobility transistors on high-quality GaAs substrates (metamorphic HEMT) is of primary interest for millimeter-wave devices. These heterostructures grown on lattice mismatched substrates allow an extension of the composition range in the structures and to exploit enhanced properties, provided that the crystalline perfection of the layers as well as electrical quality are preserved. The aim of this work is to study the influence of indium mole fraction on material properties as well as its consequences on device performance.

60-GHz high power performance In/sub 0.35/Al/sub 0.65/As-In/sub 0-35/Ga/sub 0.65/As metamorphic HEMTs on GaAs

We report on a double-pulse doped, double recess In/sub 0.35/Al/sub 0.65/As-In/sub 0.35/Ga/sub 0.65/As metamorphic high electron mobility transistor (MHEMT) on GaAs substrate. This 0.15-/spl mu/m gate MHEMT exhibits excellent de characteristics, high current density of 750 mA/mm, extrinsic transconductance of 700 mS/mm. The on and off state breakdown are respectively of 5 and 13 V and defined It gate current density of 1 mA/mm. Power measurements at 60 GHz were performed on these devices. Biased between 2 and 5 V, they demonstrated a maximum output power of 390 mW/mm at 3.1 V of drain voltage with 2.8 dB power gain and a power added efficiency (PAE) of 18%. The output power at 1 dB gain compression is still of 300 mW/mm. Moreover, the linear power gain is of 5.2 dB. This is to our knowledge the best output power density of any MHEMT reported at this frequency.

High-power V-band Ga/sub 0.51/In/sub 0.49/P/In/sub 0.2/Ga/sub 0.8/As pseudomorphic HEMT grown by gas source molecular beam epitaxy

A 0.1-μm T-gate pseudomorphic Ga/sub 0.51/In/sub 0.49/P/In/sub 0.2/Ga/sub 0.8/As/GaAs high electron mobility transistor (PM-HEMT) has been successfully developed on GaAs substrate. Each technological step has been optimized as the growth by gas source molecular beam epitaxy (GSMBE), the ohmic contacts, and the gate recess for high-frequency applications. This device with a single /spl delta/ doping exhibits excellent dc and radio frequency (RF) performances with a current density of 700 mA/mm in combination with a high breakdown voltage of 9 V, an extrinsic transconductance Gm higher than 700 mS/mm, and a current gain cutoff frequency Ft of 120 GHz at V/sub ds/=2 V. Power measurements at 60 GHz have been performed on these devices. They have demonstrated a maximum output power density of 560 mW/mm with 4.6-dB power gain and a power-added efficiency (PAE) of 22.5%, These are the first power results at V-band ever reported for GaInP/InGaAs/GaAs pseudomorphic HEMTs.

480-GHz

Self-aligned 0.55×3.5 μm² emitter InP/GaAsSb/InP double heterojunction bipolar transistors demonstrating an f_t of 310 GHz and an f_max of 480 GHz are reported. Common-emitter current gain of 24, together with a breakdown voltage of 4.6 V, is measured. The devices were fabricated with a triple-mesa process and easily fabricated with a new base isolation μ-airbridge design which, moreover, significantly reduced the base-collector capacitance C_BC.

f_{\max}

We report about the self-heating management of an InP double heterojunction bipolar transistor (DHBT) by the way of the thermal resistance. In order to reduce this latter, an AlInP/GaAsSb DHBT has been transferred on a silicon substrate offering a high thermal conductivity. According to our thermal resistance measurements on a 0.8 × 6 μm2 DHBT, a low thermal resistance of 1625 K/W is obtained, 65 % lower than for the same device fabricated on its own substrate of InP and which exhibited a value of 4452 K/W.

in InP/GaAsSb/InP DHBT With New Base Isolation

We report experimental radiation pattern measurements of a transverse electromagnetic horn antenna at the millimetric/sub-millimetric frontier (280-350 GHz). The antenna is fed by a monolithically integrated uni-travelling-carrier photodiode illuminated by an optical beatnote (photomixing) at 1.55 μm. The detection is performed using an electronic sub-harmonic mixer and the whole characterization system is working at room temperature. Radiation patterns are measured in the E-plane and compared with electromagnetic simulations with a good agreement.

\mu

In this letter, we report on high-speed InAlAsSb/InGaSb/InAlAsSb double heterojunction bipolar transistors (HBTs) (DHBT) fabricated using a conventional triple-mesa process. Current gain cutoff frequencies fT of 52 GHz and maximum oscillation frequencies fMAX of 48 GHz were extracted from measured scattering parameters for devices with 1 ×15 ¿m2 emitter size. To the best of our knowledge, these results are the first RF performance ever reported, and they demonstrate the feasibility and potential of InGaSb-based HBT for high-speed electronics applications.

-Airbridge Design

Selective wet etching of Ga_0.5In_0.5Sb on Al_0.55In_0.45Sb and Al_0.55In_0.45Sb on Ga_0.5In_0.5Sb were demonstrated using tartaric acid and hydrochloric acid based solutions, respectively. Controllable etch rates in the range 400-1000 Aring/min resulting in smooth surfaces and selectivities of >10 suitable for use in HBT processing were achieved. By calculating the activation energies, we also determined the rate-limiting step in the etching.

InP HBT Thermal Management by Transferring to High Thermal Conductivity Silicon Substrate

E-Beam processed GaN-based Schottky diodes for microwave, millimeter-wave power applications were characterized under both small-signal and large-signal conditions. A Large-Signal Network Analyzer was used and equivalent circuit models were obtained by combining small signal S-parameter data with large-signal time-domain waveform optimization. The impact of anode diameter size and layer design were investigated and the active layer thickness dependence of the intrinsic elements was analyzed. Large-signal measurements allowed device non-linearity evaluation.