C.W. Farley

LWIR 128*128 GaAs/AlGaAs multiple quantum well hybrid focal plane array

The authors describe the fabrication and performance of a new type of hybrid focal plane array (FPA). The hybrid consists of a 128*128 GaAs/AlGaAs superlattice multiple-quantum-well detector array with peak response at 7.7 mu m mated to a high-performance CMOS readout with direct injection input. The quantum-well infrared photodetector (QWIP) array was fabricated by molecular-beam epitaxy (MBE). Optical gratings were excluded to facilitate evaluation of the basic detector-technology. The mean D* at 78 K was 5.76*10/sup 9/ cm- square root Hz/W. Total FPA 1/f noise was negligible, as corroborated by imagery having minimum resolvable temperature (MRT) of 30 mK at 0.07 cycles/mrad. No gain nonuniformity correction was used in the imaging demonstration. >

A high-speed, low-power divide-by-4 frequency divider implemented with AlInAs/GaInAs HBT's

The authors describe the first frequency divider demonstrated using AlInAs/GaInAs heterojunction bipolar transistors (HBTs). The divider (a static 1/4 divider circuit) operates up to a maximum frequency of 17.1 GHz, corresponding to a gate delay of 29 ps for a bilevel current-mode logic (CML) gate with a fan-out of 2, and a total power consumption of 67 mW (about 4.5 mW per equivalent NOR gate). These results demonstrate the potential of AlInAs/GaInAs HBTs for implementing low-power, high-speed integrated circuits.<<ETX>>

25 GHz HBT frequency dividers

A report is presented on a regenerative frequency divider and a static frequency divider implemented with (AlGa)As/GaAs heterojunction bipolar transistors (HBTs). Both dividers have been operated at input frequencies higher than 25 GHz. Also described is a frequency divider implemented with AlInAs/GaInAs HBTs operating up to 17.1 GHz, at considerably reduced power. These frequency dividers are among the fastest ever reported for each of these circuit types and illustrate the feasibility of using direct frequency division in microwave systems up to K/sub u/ band.<<ETX>>

InP-based heterojunction bipolar transistors: performance status and circuit applications

The present status and prospects of heterojunction bipolar transistors configured with InP, InGaAs and/or InAlAs on InP substrates are reviewed. The importance of ultrahigh electron velocity is highlighted. Self-aligned fabrication techniques are described, and devices with wide bandgap collectors for microwave power applications and with low turn-on voltage for digital applications are presented. Applications are discussed. Frequency dividers configured with these devices have operated to 17 GHz.<<ETX>>

High speed AlGaAs/GaAs complementary HBT technology realized by multiple MBE growth and merged processing

A high-performance monolithic Npn/Pnp complementary HBT (heterojunction bipolar transistor) technology involving multiple MBE (molecular beam epitaxy) growths has been developed. Many of the process steps have been merged to simplify concurrent fabrication of Npn and Pnp devices. Pnp devices exhibit f/sub T/=20 GHz and f/sub max/=19 GHz. Npn devices show f/sub T/=51 GHz and f/sub max/=60 GHz. These cutoff frequencies are 2 to 3 times values previously reported for monolithically integrated Npn and Pnp devices. For the first time, integrated circuits operating at microwave frequencies have been fabricated from both types of devices on the same wafer. Npn-based direct coupled feedback amplifiers (gain blocks) show a gain of 11 dB and a 3-dB bandwidth of 12 GHz. Pnp-based gain blocks show a gain of 8 dB and a 3-dB bandwidth of 6 GHz.<<ETX>>

Base recombination of high performance InGaAs/InP HBT's

Summary form only given. The authors have measured the gain of InGaAs HBTs (heterojunction bipolar transistors) as a function of base doping, with Zn and Be, using MOCVD (metal-organic chemical vapor deposition), and with C, using gas source MBE (molecular beam epitaxy), in the range of 5*10/sup 18/ to 8*10/sup 19/. Large area devices were measured at 2 kA/cm/sup 2/, where DC gain is saturated. Single HBTs, and double HBTs with graded base-collector junctions, were compared. Zn doping gave the highest figure of merit (HFE/R/sub bs//sup 2/), but the tendency for Zn to diffuse at high concentrations produced low collector breakdown voltage. Be doping resulted in high V/sub bc/>6 V at very low r/sub o/, >

Ultra-high speed p-i-n/HBT monolithic OEIC photoreceiver

Summary form only given. An extremely wide-bandwidth monolithic OEIC receiver with high gain and low noise is described. It demonstrates the ability of HBT technology to provide low-noise and high-bandwidth performance in a preamplifier combined with an easily and naturally integrable optical detector. A circuit topology is also demonstrated to yield good high-speed performance with GaAs-AlGaAs HBTs. With minor modifications and improvements both speed and quantum efficiency should be easily increased. This approach can be extended into the InGaAs-InAlAs or InGaAs-InP system to provide operation at 1.3 and 1.55 mu m. >

62 GHz monolithic multistage indium phosphide-based HEMT amplifier

The superior performance qualities of indium phosphide-based high electron mobility transistor (HEMT) structures have already been established with discrete devices. In this paper, the first V-band monolithic millimeter-wave ICs made with this material system are reported. Results are presented for a monolithic amplifier with a 9 dB gain at 62.5 GHz. These circuits have all the necessary components for a high-performance amplifier technology including quarter-micron EBL (electron beam lithography) defined gates, MIM (metal insulator metal) capacitors, air-bridge metal crossovers and plated-thru-substrate vias to the ground plane.<<ETX>>

High performance AlInAs/GaInAs HBTs for high speed, low power digital circuits

Summary form only given. The authors describe high-performance single-heterojunction (SH) and double-heterostructure (DH) AlInAs/GaInAs HBTs (heterojunction bipolar transistors) for low-power digital circuits. They report record results in both DC and RF performance of AlInAs/GaInAs HBTs and circuits, including the highest unity current gain frequency, f/sub t/=78 GHz, reported for AlInAs/GaInAs HBTs, and a divide-by-four frequency divider operating up to a frequency of 17.1 GHz with a total power consumption of only 67 mW. >

Monolithic indium phosphide-based HEMT multioctave distributed amplifier

The superior performance qualities of indium-phosphide-based high-electron-mobility transistor (HEMT) structures has been established with discrete devices. A report is presented on the first monolithic ICs made with this material system. MBE grown AlInAs/GaInAs HEMT layer on an InP substrate. Results are presented on a monolithic distributed amplifier with greater than 10-dB gain from 2 to 30 GHz. At 14 GHz, the noise figure was 5.2 dB with 14 dB of associated gain. These circuits have all the necessary components for a high-performance amplifier, including quarter-micron EBL (electron beam lithography) defined gates, MIM (metal-insulator-metal) capacitors, air-bridge metal crossovers, and plated-through-substrate vias to the ground plane.<<ETX>>