L.M. Lunardi

High-speed monolithic p-i-n/HBT and HPT/HBT photoreceivers implemented with simple phototransistor structure

Monolithic photoreceivers, using the base-collector junction of an InP/InGaAs phototransistor structure for a p-i-n photodetector, have been fabricated for the first time. Bandwidths as high as 3 GHz and bit rates as high as 5 Gb/s, with sensitivities of -22.5 dBm and -21.5 dBm for light focused on the p-i-n or on the first stage transistor of the preamplifier, respectively, have been achieved. These results represent the highest operating speed demonstrated for any phototransistor-based receiver.<<ETX>>

Implant‐induced high‐resistivity regions in InP and InGaAs

We have investigated the effects of ion bombardment on the electrical properties of intentionally doped InP and InGaAs grown by metalorganic molecular‐beam epitaxy. The sheet resistivity and mobility of n+InP (Sn) and n+InGaAs (Sn) or p+InGaAs (Be) epilayers grown on semi‐insulating InP substrates were measured as a function of ion species (O, B, H, or Fe), ion dose (1012–1015 cm−2), and post‐implant annealing temperature (100–600 °C). In n+InP, the resistivity after bombardment goes through a maximum with annealing temperature, reaching a value of ∼106 Ω/⧠ for 0.5‐μm‐thick films after implantation with H or O and annealing at 200–300 °C. The as‐grown resistivity is restored by annealing above 500 °C. Ion doses below 1012 cm−2 actually lead to a decrease in resistivity through the creation of shallow donor levels. By contrast, the implantation of Fe above a critical dose where the Fe density exceeds the dopant concentration leads to the formation of thermally stable, high‐resistivity (>106 Ω/⧠) material. ...

20-Gb/s monolithic p-i-n/HBT photoreceiver module for 1.55-μm applications

A photoreceiver, composed of a p-i-n photodetector monolithically integrated with an InP-InGaAs heterojunction bipolar transistor (HBT)-based transimpedance amplifier, has been fabricated from metal-organic molecular beam epitaxy (MOMBE) material. The fiber-pigtailed module has measured sensitivities of -20.4 dBm and -17.0 dBm for data rates of 10 Gb/s and 20 Gb/s, respectively, at a bit-error-rate of 1/spl times/10/sup -9/. High-speed operation has been achieved with modest (3 /spl mu/m) device dimensions. These results are the best ever reported for an OEIC photoreceiver at these speeds.<<ETX>>

A 12-Gb/s high-performance, high-sensitivity monolithic p-i-n/HBT photoreceiver module for long-wavelength transmission systems

A very high sensitivity, high speed, fiber-pigtailed photoreceiver module is described. The OEIC photoreceiver, composed of a p-i-n photodetector monolithically integrated with an InP-InGaAs heterojunction bipolar transistor (HBT)-based transimpedance amplifier, has measured sensitivity of -20 dBm and -17.6 dBm for data rates of 10 and 12 Gb/s, respectively, at a bit error rate of 1/spl times/10/sup -9/. These results are the best ever reported for an OEIC photoreceiver at these speeds. In an optical transmission experiment with a low noise erbium-doped fiber amplifier (EDFA) preceding the OEIC photoreceiver, the measured sensitivities were -35.2 and -32 dBm at 10 and 12 Gb/s respectively.<<ETX>>

Monolithic eight-wavelength demultiplexed receiver for dense WDM applications

A single chip incorporating a waveguide grating router and eight p-i-n photodetectors followed by eight preamplifiers constructed from heterojunction bipolar transistors, has been realized. The chip can demultiplex eight wavelengths spaced 100 GHz (0.81 nm) apart with nearest neighbor crosstalk better than -15 dB. The external quantum efficiency for each of the eight wavelength demultiplexed photodetectors was 5-8% (a responsivity of 0.06-0.10 A/W) and each optical front end operated up to 2.5 Gb/s. This is the first demonstration of monolithic integration of electronic circuits with a wavelength demultiplexer.<<ETX>>

Eight-channel p-i-n/HBT monolithic receiver array at 2.5 Gb/s per channel for WDM applications

We report a monolithic chip incorporating an eight channel p-i-n/HBT photoreceiver array designed for multichannel WDM applications. The p-i-n photodetectors are edge illuminated and centered at a 250 /spl mu/m pitch for mating with either ribbon fiber connectors or waveguide demultiplexers. Each channel operates at 2.5 Gb/s with an electrical crosstalk of -20 dB between adjacent channels. The average sensitivity of each receiver in the array was measured to be (-20/spl plusmn/1) dBm for a bit error rate of 10/sup -9/ at a wavelength of 1.5 /spl mu/m.<<ETX>>

High-speed, high-current-gain p-n-p InP/InGaAs heterojunction bipolar transistors

p-n-p InP/InGaAs heterojunction bipolar transistors (HBTs) are reported for the first time. The transistors, grown by metal organic molecular beam epitaxy (MOMBE), exhibited maximum DC current gain values up to 420 for a base doping level of 4*10/sup 18/ cm/sup -3/. Small-signal measurements on self-aligned transistors with 3- mu m*8- mu m emitter area indicated the unity gain cutoff frequency value of 10.5 GHz and the inferred maximum frequency of oscillation of 25 GHz. The results clearly demonstrate the feasibility of complementary integrated circuits in the InP material system.<<ETX>>

Investigation of crosstalk performance of eight-channel p-i-n/HBT OEIC photoreceiver array modules

Detailed measurements of crosstalk under multichannel operation of several eight-channel p-i-n/HBT monolithic array photoreceiver modules are reported. At an operating speed of 2.5 Gb/s, with an average sensitivity of -25 dBm, crosstalk penalties ranging from 0.2 dB to 2.6 dB for a bit-error rate of 10/sup -9/ have been measured for adjacent channels receiving -22 dBm to -12 dBm of optical signal power. This is the first report of the crosstalk performance of a fully packaged OEIC array photoreceiver module.

A planar-doped 2D-hole gas base AlGaAs/GaAs heterojunction bipolar transistor grown by molecular beam epitaxy

A novel type of AlGaAs/GaAs heterojunction bipolar transistor (HBT) which uses a two-dimensional (2-D) hole gas base formed by planar doping using molecular-beam epitaxy (MBE) has been demonstrated. The base consists of a submonolayer of Be atoms of sheet concentration 0.5-5*10/sup 13/ cm/sup -2/ which is deposited during growth interruption by MBE. The transistor structure exhibits DC current gains up to 700. The effective base transit time is negligible in these transistors and it is postulated that very high-speed nonequilibrium transport may occur in the collector region.<<ETX>>

Microwave multiple-state resonant tunneling bipolar transistors

Fabrication and microwave performance of a multiple-state resonant-tunneling bipolar transistor (RTBT) are presented. This transistor exhibits a maximum DC current gain of 60 at room temperature and a cutoff frequency of 24 GHz. Frequency multiplication by a factor of five has been demonstrated with a single transistor.<<ETX>>