Thomas R. Block

A 108-GHz InP-HBT monolithic push-push VCO with low phase noise and wide tuning bandwidth

This paper reports on what is believed to be the highest frequency bipolar voltage-controlled oscillator (VCO) monolithic microwave integrated circuit (MMIC) so far reported. The W-band VCO is based on a push-push oscillator topology, which employs InP HBT technology with peak f/sub T/s and f/sub max/s of 75 and 200 GHz, respectively. The W-band VCO produces a maximum oscillating frequency of 108 GHz and delivers an output power of +0.92 dBm into 50 /spl Omega/. The VCO also obtains a tuning bandwidth of 2.73 GHz or 2.6% using a monolithic varactor. A phase noise of -88 dBc/Hz and -109 dBc/Hz is achieved at 1- and 10-MHz offsets, respectively, and is believed to be the lowest phase noise reported for a monolithic W-band VCO. The push-push VCO design approach demonstrated in this work enables higher VCO frequency operation, lower noise performance, and smaller size, which is attractive for millimeter-wave frequency source applications.

0.10 /spl mu/m graded InGaAs channel InP HEMT with 305 GHz f/sub T/ and 340 GHz f/sub max/

We report here 305 GHz f/sub T/, 340 GHz f/sub max/, and 1550 mS/mm extrinsic g/sub m/ from a 0.10 /spl mu/m In/sub x/Ga/sub 1-x/As/In/sub 0.62/Al/sub 0.48/As/InP HEMT with x graded from 0.60 to 0.80. This device has the highest f/sub T/ yet reported for a 0.10 /spl mu/m gate length and the highest combination of f/sub T/ and f/sub max/ reported for any three-terminal device. This performance is achieved by using a graded-channel design which simultaneously increases the effective indium composition of the channel while optimizing channel thickness.<<ETX>>

ROLE OF MISFIT DISLOCATIONS ON PSEUDOMORPHIC HIGH ELECTRON MOBILITY TRANSISTORS

The relationship between structural defects and device performance of In0.21Ga0.79As/(Al,Ga)As high electron mobility transistors with different In0.21Ga0.79As channel thicknesses (75–300 A) was analyzed. Using triple axis x‐ray diffraction and transmission electron microscopy, we determined that the presence of misfit dislocations along only one of the 〈110〉 directions did not impair device performance. In fact, the sample with the highest cutoff frequency possessed the misfit dislocations along one 〈110〉 direction. However, for thicker samples, with an orthogonal array of misfit dislocations, the device parameters were significantly degraded. We also determined that x‐ray diffuse scattering correlates strongly with device performance, making this nondestructive technique useful for device performance evaluation.

A DC-20-GHz InP HBT balanced analog multiplier for high-data-rate direct-digital modulation and fiber-optic receiver applications

This paper reports on a dc-20-GHz InP heterojunction bipolar transistor (HBT) active mixer, which obtains the highest gain-bandwidth product (GBP) thus far reported for a direct-coupled analog mixer integrated circuit (IC). The InP HBT active mixer is based on the Gilbert transconductance multiplier cell and integrates RF, local oscillator, and IF amplifiers, High-speed 70-GHz f/sub T/ and 160-GHz f/sub max/ InP HBT devices along with microwave matching accounts for its record performance. Operated as a down-converter mixer, the monolithic microwave integrated circuit achieves an RF bandwidth (BW) from dc-20 GHz with 15.3-dB gain and benchmarks a factor of two improvement in GBP over state-of-the-art analog mixer ICs. Operated as an up-converter, direct-digital modulation of a 2.4-Gb/s 2/sup 31/ -1 pseudorandom bit sequence (PRBS) onto a 20-GHz carrier frequency resulted in a carrier rejection of a 28 dB, clock suppression of 35 dBc, and less than a 50-ps demodulated eye phase jitter. The analog multiplier was also operated as a variable gain amplifier, which obtained 20-dB gain with a BW from dc-18 GHz, an third-order intercept of 12 dBm, and over 25 dB of dynamic range. A single-ended peak-to-peak output voltage of 600 mV was obtained with a /spl plusmn/35-mV 15 Gb/s 2/sup 5/-1 PRES input demonstrating feasibility for OC-192 fiber-telecommunication data rates. The InP-based analog multiplier IC is an attractive building block for several wideband communications such as those employed in satellites, local multipoint distribution systems, high-speed local area networks, and fiber-optic links.

Extending the bandwidth performance of heterojunction bipolar transistor-based distributed amplifiers

An InAlAs-InGaAs-InP HBT CPW distributed amplifier (DA) with a 2-30 GHz 1-dB bandwidth has been demonstrated which benchmarks the widest bandwidth reported for an HBT DA. The DA combines a 100 GHz fmax and 60 GHz fT HBT technology with a cascode coplanar waveguide DA topology to achieve this record bandwidth. The cascode gain cell offers 5-7 dB more available gain (MAG) than a common-emitter, and is used to extend the amplifiers upper frequency performance. A coplanar waveguide design environment is used to simplify the modeling and fabrication, as well as to reduce the size of the amplifier. Novel active load terminations for extending the DAs lower frequency response were separately demonstrated. The active loads are capable of extending the lower bandwidth performance by two decades resulting in performance below 45 MHz. This work explores both design techniques and technology capability which can be applied to other distributively matched HBT circuits such as active baluns for mixers, active combiners/dividers, and low DC power-broadband amplifiers.

A 44-GHz-high IP3 InP HBT MMIC amplifier for low DC power millimeter-wave receiver applications

This paper reports on what is believed to be the highest IP3/P/sub dc/ power linearity figure of merit achieved from a monolithic microwave integrated circuit (MMIC) amplifier at millimeter-wave frequencies. The 44 GHz amplifier is based on an InP heterojunction bipolar transistor (HBT) technology with f/sub T/s and f/sub max/s of 70 and 200 GHz, respectively. The 44-GHz amplifier design consists of four prematched 1/spl times/l0/spl mu/m/sup 2/ four-finger (40-/spl mu/m/sup 2/) heterojunction bipolar transistor (HBT) cells combined in parallel using a compact /spl lambda//8 four-way microstrip combiner. Over a 44-50-GHz frequency band, the amplifier obtains a gain of 5.5-6 dB and a peak gain of 6.8-7.6 dB under optimum gain bias. At a low bias current of 48 mA and a total dc power of 120 mW, the amplifier obtains a peak IP3 of 34 dBm, which corresponds to an IP3/P/sub dc/ power ratio of 21:1, a factor of two better than previous state-of-the-art MMICs reported in this frequency range. By employing a thin, lightly doped HBT collector epitaxy design tailored for lower voltage and higher IP3, a record IP3/P/sub dc/, power ratio of 42.4:1 was also obtained and is believed to be the highest reported for an MMIC amplifier of any technology. The new high-linearity HBTs have strong implications for millimeter-wave receiver as well as low-voltage wireless applications.

0.1 /spl mu/m InGaAs/InAlAs/InP HEMT MMICs - a flight qualified technology

0.1 /spl mu/m InGaAs/InAlAs/InP HEMT MMIC technology on 3- inch InP substrates has been qualified in the categories of three-temperature lifetest, gamma radiation, RF survivability, electrostatic discharge, via-hole baking, and H/sub 2/ poisoning. The three-temperature lifetest (T/sub 1/ = 215/spl deg/C, T/sub 2/ = 230/spl deg/C and T/sub 3/ = 250/spl deg/C) of 0.1 /spl mu/m InGaAs/InAlAs/InP HEMT MMICs in a N/sub 2/ ambient demonstrates an activation energy (Ea) as high as 1.9 eV, achieving a projected median-time-to-failure (MTF) /spl ap/ 1/spl times/10/sup 8/ hours at a 125/spl deg/C junction temperature. Gamma radiation up to 5 mega RAD dose does not induce any degradation of DC/RF characteristics. Electrostatic discharge (ESD) shows destructive voltage up to 100 Volts. Furthermore, 0.1 /spl mu/m InP HEMTs exhibit less sensitivity to H/sub 2/ exposure than 0.1 /spl mu/m GaAs pseudomorphic HEMTs. The qualification results demonstrate the readiness of 0.1 /spl mu/m InGaAs/InAlAs/InP MMICs technology for flight applications.

The effect of RF-driven gate current on DC/RF performance in GaAs pHEMT MMIC power amplifiers

This paper describes RF-driven gate current effects on the dc/RF performance of 0.15-/spl mu/m (gate length) 2-mil (substrate thickness) GaAs pseudomorphic high-electron mobility transistor (pHEMT) monolithic microwave integrated circuit power amplifiers (PAs). High gate current is generated in PAs under RF drive at room temperature. A long-term lifetest of PAs with various gate currents induced by RF drive was performed to investigate the effect of RF-driven gate current on dc/RF performance in GaAs pHEMT PAs. Accordingly, an empirical model was developed to predict the dc/RF performance of V-band PA modules by the end of life (EOL). This information is crucial for system engineers in order to budget sufficient output power so that the system can still maintain performance capability by EOL.

Commercial heterojunction bipolar transistor production by molecular beam epitaxy

We have developed the first commercial heterojunction bipolar transistor (HBT) production line based on GaAs–AlGaAs–InGaAs HBT material grown by molecular beam epitaxy. We have demonstrated sustained high‐yield production of HBT integrated circuits for commercial applications using molecular beam epitaxy growth and processing techniques originally developed for high‐reliability applications. TRW HBT parts such as cellular power amplifiers, digital radio chip sets, Darlington gain blocks, and analog‐to‐digital convertors are now inserted in high volume commercial products such as cellular phones, local area networks, and digital oscilloscopes. HBT monolithic microwave integrated circuits allow these products to achieve functions and performance never before available for consumer applications.

High performance and high reliability InP HEMT low noise amplifiers for phased-array applications

This paper describes the development of a Q-band low noise amplifier unit using a 0.1 /spl mu/m InP HEMT MMICs that has been demonstrated with high RF performance and high reliability over a frequency band from 43.5 to 45.5 GHz at Northrop Grumman Space Technology (NGST). The InP HEMT LNAs with high RF performance and high reliability are crucial for the advanced phased-array applications. The module demonstrates superior performance with gain greater than 30.1 dB and noise figure less than 3.2 dB over the frequency band of 43.5 to 45.5 GHz. The InP HEMT technology has an activation energy of 1.9 eV and mean-time-to-failure of 10/sup 8/ hours at T/sub junction/ of 125/spl deg/C and these MMICs further demonstrate the readiness of NGSTs 0.1 /spl mu/m InP HEMT MMICs technology for the advanced phased-array applications.