This paper describes a manufacturable and reliable 0.1 μm AlSb/InAs MMIC technology for ultra-low power applications. AlSb/InAs HEMTs have been demonstrated with only one-tenth power dissipation of conventional InAlAs/InGaAs/InP HEMTs. The uniform DC and RF performance of AlSb/InAs HEMTs have been demonstrated on 3-inch GaAs substrates. The further demonstration of reliable AlSb/InAs HEMT technology warrants the successful insertion of AlSb/InAs HEMT MMICs for military and space applications with ultra-low power requirements.
In this letter, low noise amplification at 0.67 THz is demonstrated for the first time. A packaged InP High Electron Mobility Transistor (HEMT) amplifier is reported to achieve a noise figure of 13 dB with an associated gain greater than 7 dB at 670 GHz using a high f MAX InP HEMT transistors in a 5 stage coplanar waveguide integrated circuit. A 10-stage version is also reported to reach a peak gain of 30 dB. These results indicate that InP HEMT integrated circuits can be useful at frequencies approaching a terahertz.
In this letter, we demonstrate the first 400 GHz multiplier chain with integrated buffer amplifiers through the chain. The x9 multiplier chain uses 25 nm InP HEMT MMIC technology. The chain consists of three packaged MMICs in split-block waveguide packages with each multiplier incorporating an integrated output buffer. We report a peak output of 6.9 mW and greater than 4 mW over a 10% bandwidth.
Maximizing In composition in the channel structures of high-electron-mobility transistors on InP is one important aspect of achieving devices capable of operating beyond 300 GHz. In this article, we compare dc and rf performance results from two variations of one such device design, incorporating a composite-channel structure comprised of InAs clad by InP-lattice-matched InGaAs. The only difference between these two variations is the thickness of the bottom InGaAs cladding layer. The thicker gave extremely high performance, with current-gain-cutoff frequency (f T ) exceeding 500 GHz, enabled by room-temperature channel-electron Hall mobility (mu e ) as high as 15,400 cm 2 /V/s and dc transconductance (g m ) exceeding 2700 mS/mm; but it also incurred significant impact ionization. The thinner incurred less of this short-channel effect and yet gave very high performance, with f T exceeding 440 GHz, enabled by mu e as high as 14,800 cm 2 /V/s and g m exceeding 2200 mS/mm, initially indicating that such a tradeoff might be the more overall beneficial. However, from a subsequent process iteration, in which the gate-recess etch was deepened for reduced short-channel effects, both of these same composite-channel design variations gave even better performance results. In that process iteration, the thicker variation not only achieved f T exceeding 500 GHz, but also achieved the recently-published new record maximum frequency of oscillation (f MAX ) exceeding 1 THz. Therefore, the thicker bottom InGaAs cladding layer has indeed proven to be the more optimal composite-channel design variation for performance beyond 300 GHz.
We show on-wafer measured data for four amplifier designs targeting the WR1.5 band. One design shows gain exceeding 20 dB over the entire WR1.5 bandwidth. We show the maturation of the InP HEMT process, and show that now fewer gain stages are necessary to achieve comparable gain numbers reported in past publications. We also show that gain is achievable with larger device peripheries. These larger periphery devices should ultimately allow for greater saturated output power levels, though this is not confirmed at the time of this writing.
In/sub x/Al/sub 1-x/As/In/sub x/Ga/sub 1-x/As heterojunction bipolar transistors (HBTs) with indium composition ranging from 86 to 100% were grown on InP substrates using strain-relief compositionally graded In/sub x/Al/sub 1-x/As buffers. Lattice-matched In/sub 0.86/Al/sub 0.14/As/In/sub 0.86/Ga/sub 0.14/As single and double HBTs with large and small emitter active areas have been successfully fabricated on 6.00 /spl Aring/ graded buffer layers. Despite the use of narrow band gap material system, practical breakdown voltages exceeding 1.5 V have been demonstrated from DHBT structures with high DC gain, reduced leakage at the device junctions and turn-on voltage reduction by a factor of two compared to existing InP bipolar technology.
In this paper, electrical characteristics from MBE-grown metamorphic HBTs with indium composition will be presented. I-V measurements and leakage measurements can be carried out in this report.
Pivotal in the design of circuits is the ability to efficiently translate available transistor gain to high gain per stage. Remarkably, for 35-nm InP HEMT transistors, the efficiency of this translation remains high even up to ~0.5 THz. The ever shrinking wavelength correlated with higher frequencies necessitates a scaling of not only the device layout, but also of the passive elements and wafer thickness. Furthermore, to avoid distributed effects, the length of transistor gate fingers must be reduced.
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