InP Double Heterojunction Bipolar Transistor Research Articles

Mux-driver-EAM in single module – a solution for ultra-high bit rate applications

The integration of the final three higher-speed functions of an electro-optical emitter in a single module – the multiplexer, the driver and the electroabsorption modulator (EAM) – is demonstrated. The module has operated up to a bit rate of 40 Gbit/s. The Mux-driver was made using in-house InP-double heterojunction bipolar transistor technology. The proposed solution has the following features: compactness, low bit rate inputs, no need of a bandpass capacitor or bias tee between driver and EAM, and possibility to adjust the driving offset voltage, electrical control output, low power consumption, etc.

High-frequency performance of metamorphic InP/In 0.53Ga 0.47As/InP DHBT in common base configuration on GaAs substrates

In this work, we report the detailed high-frequency noise and power characterization of metamorphic InP double heterojunction bipolar transistors in common base configuration. The noise and power performances were investigated for 5×10 μm 2 device. A minimum noise figure of 2.3 dB with an associated gain of 14.5 dB at 2 GHz, and a maximum output power of 13.0 dBm with a power added efficiency of 47.8% at 2.4 GHz were obtained.

Highest efficiency, linear X-band performance using InP DHBTs - 48% PAE at 30 dB C/IM3

InP single heterojunction bipolar transistors have previously demonstrated 5-10 dB lower third-order intermodulation products (IM3) compared to GaAs heterojunction bipolar transistors (HBTs) under low voltage (2 V) operation. This paper reports excellent single-tone and two-tone X-band operation, including high two-tone power-added efficiency (PAE), on linear InP double heterojunction bipolar transistors (DHBTs) operated at V/sub ce/=4 V. The InP DHBT demonstrated a 30 dB carrier to third-order intermodulation product (C/IM3) output power ratio simultaneously with 48% two-tone PAE. This is the highest known efficiency of an X-band device under linear (30 dB C/IM3) operation. This is especially significant for microwave power amplifiers for satellite communication transmitters, where lower intermodulation distortion is normally accomplished by backing off in RF drive and output power, thus sacrificing PAE performance.

InP/GaAsSb/InP double HBTs: a new alternative for InP-based DHBTs

We report on the physical operation and performance of MOCVD-grown abrupt heterojunction InP/GaAs/sub 0.51/Sb/sub 0.49//InP double heterojunction bipolar transistors (DHBTs). In particular, the effect of the InP collector thickness on the breakdown voltage and on the current gain cutoff frequency is assessed and a f/sub T/ of 106 GHz is reported for a DHBT with a 400 /spl Aring/ base and a 2000 /spl Aring/ InP collector with a BV/sub CEO/ of 8 V. We show that InP/GaAsSb/InP DHBTs are characterized by a weak variation of f/sub T/ as a function of temperature. Finally, we also demonstrate that high maximum oscillation frequencies f/sub MAX/>f/sub T/ can be achieved in scaled high-speed InP/GaAsSb/InP DHBTs, and provide estimates of the maximum cutoff frequencies achievable for this emergent but promising material system. Recent results on improved structures validate our performance predictions with cutoff frequencies well beyond 200 GHz.

Design and performance of InP/GaAsSb/InP double heterojunction bipolar transistors

We report a fabrication technique for 1 μm wide emitter finger InP/GaAs0.51Sb0.49/InP double heterojunction bipolar transistors (DHBTs). In this technology, we use a wet-etched undercut airbridge technique to provide device isolation while minimizing parasitics and avoiding damage to semiconductor layers by dry etching. The metalorganic chemical vapor deposition-grown InP/GaAs0.51Sb0.49/InP NpN structure takes advantage of a staggered (“type II”) band lineup at InP/GaAs0.51Sb0.49 interfaces: in this material system the GaAs0.51Sb0.49 base conduction band edge lies 0.18 eV above the InP collector conduction band, thus enabling the implementation of InP collectors free of the collector current blocking effect encountered in conventional Ga0.47In0.53As base DHBTs. The structure results in very low collector current offset voltages, low emitter-base turn-on voltages, and very nearly ideal base and collector current characteristics with junction ideality factors of nB=1.05 and nC=1.00 and DHBTs with cutoff frequencies as high as 106 GHz and breakdown voltages of BVceo=8 V have been implemented, and represent the highest performance ever achieved in this material system. The low turn-on and offset voltages make InP/GaAs0.51Sb0.49/InP DHBTs attractive for long talk-time wireless communication systems, yet these devices can also be adapted to power applications by virtue of their InP collector. Excellent performances are obtained without the need for complex and critical optimizations thanks to the favorable band lineups: all junctions are abrupt and no grading was performed in doping or in material composition.

Non-blocking collector InP/GaAs/sub 0.51/Sb/sub 0.49//InP double heterojunction bipolar transistors with a staggered lineup base-collector junction

We have developed lattice-matched InP/GaAs/sub 0.51/Sb/sub 0.49//InP NpN double heterojunction bipolar transistors (DHBTs) which take advantage of the staggered ("type II") band lineup at InP/GaAs/sub 0.51/Sb/sub 0.49/ interfaces: in this system the GaAs/sub 0.51/Sb/sub 0.49/ base conduction band edge lies /spl sim/0.18 eV above the InP collector conduction band, thus enabling the implementation of InP collectors free of the current blocking effect encountered in conventional Ga/sub 0.47/In/sub 0.53/As base DHBTs. The structure results in very low collector current offset voltages, low emitter-base turn-on voltages, and very nearly ideal base and collector current characteristics with junction ideality factors of n/sub B/=1.05 and n/sub c/=1.00. InP/GaAs/sub 0.51/Sb/sub 0.49//InP DHBTs appear well-suited to low-power applications, but can also be used in power applications by virtue of their InP collector. The symmetry of the transistor band structure also lends itself to the potential integration of collector-up and emitter-up devices.

Metalorganic vapor phase epitaxy of high-quality GaAs0.5Sb0.5 and its application to heterostructure bipolar transistors

We report the growth and characterization of high-quality InP/GaAs0.5Sb0.5/InP heterostructures and their application to double-heterojunction bipolar transistors (DHBT). The GaAs0.5Sb0.5 layer quality was evaluated by high-resolution x-ray diffraction (XRD), low-temperature photoluminescence (PL), and atomic force microscopy (AFM). The observed 4.2 K PL linewidth was 7.7 meV and XRD rocking curves matched those of dynamical scattering simulations. In contrast to previously reported InP/GaAs0.5Sb0.5/InP DHBTs, the present devices show nearly ideal base and collector currents, low turn-on and collector offset voltages, and a high current gain. Self-aligned DHBTs exhibit a cutoff frequency over 75 GHz and common-emitter current gain greater than 100 at 300 K.

InP DHBT technology and design methodology for high-bit-rate optical communications circuits

High-bit-rate optical communication links require high performance circuits. Electrical time division multiplex (ETDM) single channel bit-rate of 40 Gb/s is at hand, due to recent progress in both technology and design methodology. Multilevel modulation format can be envisaged for ETDM transmission. An InP double heterojunction bipolar transistor technology is presented in this paper. The methodology used and tools developed with optical communications in mind are also discussed. Fabricated circuits are reported: 40 Gb/s multiplexer and demultiplexer, a 20 Gb/s driver, a 30 Gb/s selector-driver, a 22 Gb/s decision circuit, and a decision-decoding circuit for multilevel transmissions.

High f/sub max/ InP double heterojunction bipolar transistors with chirped InGaAs/InP superlattice base-collector junction grown by CBE

We report the performance of InP Double Heterojunction Bipolar Transistors (DHBT's) with a chirped InGaAs/InP superlattice B-C junction grown by CBE. The B-C junction of the DHBT was graded with a 10-period InGaAs/InP chirped superlattice (CSL) between the InGaAs base and the lightly doped InP collector. A highly doped thin layer was also included at the end of the CSL to offset the quasi-electric field arising from the grade and suppress further the carrier blocking effect across the B-C heterojunction. The InP/InGaAs CSL DHBT demonstrated a high BV/sub CEO/ of 18.3 V with a typical current gain of 55 with minimal carrier blocking up to high current densities. Maximum cutoff frequencies of f/sub max/=146 GHz and f/sub r/=71 GHz were obtained from the fabricated 2/spl times/10 /spl mu/m/sup 2/-emitter DHBT.

Low-frequency noise in InP-based NnPnN double heterojunction bipolar transistors

This letter deals with the low-frequency noise in an InGaAs(P)/InP double heterojunction bipolar transistor at room temperature. The recombination is mainly responsible for the noise. The current dependence of the base noise with floating collector was of the form IB3 and the shot noise of base current corresponding to 3.2×10−24 A2/Hz for f=10 Hz. The current dependence of the collector noise with high frequency short circuited was of the form Ic1.55 and the shot noise of collector current corresponding to 3.2×10−24 A2/Hz for f=10 Hz.

Fabrication of InP-based NnpnN heterojunction bipolar transistor

InGaAs(P)/InP double heterojunction bipolar transistors have been successfully fabricated by inserting an n-type InGaAsP (Eg=0.95 eV) quaternary (0.1 μm, undoped) layer on either side of the base by liquid-phase epitaxy (LPE). As we know, it is the first time to grow this structure by LPE. These devices have been fabricated using a non-self-aligned technology. In this case it can improve the common-emitter current/voltage (IC /VCE) characteristics. Small signal current gain hfe about 100 and dc current gain hFE about 80 at IC=38 mA can be obtained. The ideality factor of emitter-base junction is 1.43.