Over 80 Gbit/s 2:1 multiplexer and low power selector ICs using InP/InGaAs DHBTs

A 2:1 multiplexer (MUX) and low power selector ICs have been successfully designed and manufactured using an InP/InGaAs DHBT technology. The 2:1 MUX has been tested at data rates up to 80 Gbit/s with an output swing of 600 mV, while the selector IC has achieved operation speed up to 90 Gbit/s at a power consumption of only 385 mW.     

First hydride free GaInP/GaAs carbon doped HBT grown by CBE usingDMAAs and TBP

A current gain of 120, for a base sheet resistance of 400 Ω/□, is reported in a carbon doped base heterojunction bipolar transistor grown by chemical beam epitaxy (CBE) without hydride sources. This result is to the authors' knowledge, the best obtained with hydride free CBE for this device     

Fully-planar AlGaAs/GaAs HBT's achieved by selective CBE regrowth

This paper describes a novel fully planar AlGaAs/GaAs heterojunction bipolar transistor (HBT) technology using selective chemical beam epitaxy (CBE). Planarization is achieved by a selective regrowth of the base and collector contact layers. This process allows the simultaneous metallization of the emitter, base and collector on top of the device. For the devices with an emitter-base junction area of 2×6 μm² and a base-collector junction area of 14×6 μm², a current gain cut off frequency of 50 GHz and a maximum oscillation frequency of 30 GHz are achieved. The common emitter current gain h_FE is 25 for a collector current density J_c of 2×10⁴ A/cm²     

Comparison of InP/InGaAs DHBT distributed amplifiers as modulator drivers for 80-Gbit/s operation

This paper compares three single-ended distributed amplifiers (DAs) realized in an in-house InP/InGaAs double heterojunction bipolar transistor technology featuring an f/sub t/ and f/sub max/ larger than 200 GHz. The amplifiers use five or eight gain cells with cascode configuration and emitter follower buffering. Although the technology is optimized for mixed-signal circuits for 80 Gbit/s and beyond, DA results could be achieved that demonstrate the suitability of this process for the realization of modulator drivers. The results are documented with scattering parameter, eye diagram, and power measurements. This includes amplifiers featuring a 3-dB bandwidth exceeding 80 GHz and a gain of over 10 dB. One of the amplifiers exhibits clear eyes at 80 Gbit/s with a gain of 14.5 dB and a voltage output swing of 2.4 V/sub pp/ limited by the available digital input signal. This amplifier delivers an output power of 18 dBm (5.1 V/sub pp/) at 40 GHz and 1-dB compression. Two amplifiers offer a tunable gain peaking, which can be used to optimize circuit performance and to compensate losses in the circuit environment. The results show that, using our InP/InGaAs technology, an integration of high-speed mixed-signal circuits (e.g., multiplexers) and high-power modulator drivers on a single chip is feasible.     

InP DHBT-based distributed amplifier for 100 Gbit/s modulator driver operation

A distributed amplifier for use as a modulator driver in next generation optical data communication systems has been manufactured using InP double-hetero bipolar transistor (DHBT) technology with an emitter size of 0.7 times 1 mum². The amplifier achieved a gain of 21 dB and a 3 dB bandwidth of 120 GHz, resulting in a gain-bandwidth product of 1.35 THz. Clearly open 100 Gbit/s 231/1 non-return-to-zero pseudorandom bit sequence (NRZ PRBS) eye diagrams with an output voltage swing of 2.3 V have been measured.     

Fundamental low phase noise InP-based DHBT VCO operating up to 89 GHz

A fundamental low phase noise W-band VCO extended by an output buffer using InP/InGaAs DHBT technology is reported. The fully integrated differential VCO exhibits operation frequencies ranging from 83 to 89 GHz. At 87 GHz, a minimum phase noise of -102 dBc/Hz at 1 MHz offset frequency has been achieved. Within the tuning range, a single ended output power up to 5 dBm was measured, resulting in a total signal power of 8 dBm.     

Effect of UV-ozone oxidation on the device characteristics of InP-based heterostructure bipolar transistors

In this letter, we report the effect of UV-ozone treatments on the electrical characteristics of InGaAs/InP heterostructure bipolar transistors (HBTs). For treatments of less than 10 min, the HBT’s current gain increased with the UV-ozone exposure. This improvement is attributed to a passivation of the extrinsic base. For exposures longer than 10 min, the current gain is reduced. An increase of the base collector leakage current, leading to a degradation of the HBT’s breakdown voltage, was observed after only about 2 min of UV-ozone treatment.