Flip-chip planar GaInAs/InP p-i-n photodiodes analysis of frequencyresponse

High-speed response, high-manufacturing-yield photodiodes will be needed for optical interconnection in computer and for broadband networks. Frequency responses of a new planar GaInAs/lnP p-i-n photodiode for flip-chip bonding are analyzed. To study changes caused by the new structure, responses are related to device parameters including photoabsorption layer thickness, p-i-n junction diameter, and the size of the forward biased p-i-n junction. Forward biasing is a peculiarity of our photodiodes. A photodiode with an optimized design showed good characteristics     

Flip-chip planar GaInAs/InP p-i-n photodiode array for paralleloptical transmission

A back-illuminated planar GaInAs/InP p-i-n photodiode array with a simple fabrication process was developed for application to parallel optical transmission. Four p-i-n photodiodes were integrated in the array. The average capacitance and dark current were as low as 0.12 pF and 8 pA, respectively, at -5 V. At a 1.55-μm wavelength, the quantum efficiency of each photodiode was over 80%. The cutoff frequency was 8-10 GHz with four photodiodes when the bias voltage was -3 V and the load resistance was 50 Ω. Crosstalk between channels was -12 dB at the cutoff frequency and -45 dB at 1 GHz     

Easily manufactured high-speed back-illuminated GaInAs/InP p-i-n photodiode

A back-illuminated planar GaInAs/InP p-i-n photodiode has been fabricated with a simple fabrication process to obtain a high-speed detector. The photodiode has a capacitance as low as 54 fF, a dark current of about 3 pA, and a quantum efficiency of 74% at a 1.55- mu m wavelength. A cutoff frequency of 31 GHz was obtained when the photocurrent was about 500 mu A and the bias voltage was -10 V.<>     

Cryogenic performance of a high-speed GaInAs/InP p-i-n photodiode

The cryogenic performance of a high-speed GaInAs/InP p-i-n photodiode, with graded bandgap layers at the heterostructure interfaces, was investigated for the first time. DC measurements show that the dark current of the diode decreases sharply as the temperature decreases from 300 to 200 K. A factor of 1000 in dark current reduction was found for this photodiode, when it was cooled from room temperature to about 150 K. Similar modulation bandwidths were found for this device for temperatures between 9 and 300 K, with a bandwidth greater than 20 GHz. No degradation was found in performance at cryogenic temperature compared to room temperature. This enables direct integration of high-speed photodiodes with superconductive and other cryogenic electronics     

Planar embedded InP/GaInAs p-i-n photodiode for very high-speed operation

Planar embedded InP/GaInAs p-i-n photodiodes have been fabricated by using preferential ion-beam etching for planarizing and embedding the p-i-n photodiode structure in a semi-insulating InP substrate. The stray capacitances caused by a bonding pad and an interconnection have been markedly reduced, which resulted in extremely low capacitance of less than 0.08 pF for a diameter of 20 μm of photosensitive area. It has been demonstrated by an optical heterodyne technique that the photodiode exhibits a maximum cutoff frequency of 14 GHz. This result was analyzed taking the depletion layer thickness into account and has been found to be dominated by the carrier transit time. The demonstrated low capacitance and high-speed response result indicates the suitability of the p-i-n photodiodes not only for a discrete p-i-n photodiode but also for optoelectronic integration.     

Monolithic integration of GaInAsP/InP carrier depletion directionalcouplers and GaInAs p-i-n detectors on semi-insulating InP

Monolithic integration of two optical switches consisting in carrier depletion directional couplers based on GaInAsP/InP double heterostructure waveguides, with two GaInAs p-i-n detectors has been realized on semi-insulating InP. Packaged devices based on 2 mm coupling length directional couplers exhibit a switching voltage of -15 V and a 3 dB cutoff frequency of 1.3 GHz. Also, total fiber-to-fiber insertion loss of only 16 dB is achieved without any antireflection coating     

108-GHz GaInAs/InP p-i-n photodiodes with integrated bias tees andmatched resistors

Connections to bulk bias tees and various mismatched loads degrade the usable frequency response of high-speed photodetectors. Monolithic integration of passive components to enhance the realizable performance of high-bandwidth, long-wavelength photodiodes is demonstrated. Circuits having bias tees and matched resistors integrated with 7-μm×7-μm photodiodes show usable electrical bandwidths exceeding 100 GHz     

Highly reliable planar GaInAs/InP photodiodes with high yield madeby atmospheric pressure MOVPE

A process for making GaInAs/InP PIN photodiodes based on atmospheric pressure MOVPE is described. The technique gives devices with very low dark currents (≪1 nA) and capacitances (<0.2 pF). Yields on large area wafers greater than 80% can be achieved and extremely good reliability has been demonstrated (<0.4 FIT at 20°C)     

A high-speed eight-channel optoelectronic integrated receiver arraycomprising GaInAs p-i-n PD's and AlInAs/GaInAs HEMTs

The successful fabrication of an eight-channel optoelectronic integrated receiver array on an InP substrate, which comprises eighty elements including GaInAs p-i-n photodiodes (PDs) and AlInAs/GaInAs HEMTs, is reported. An average bandwidth of 1.2 GHz with a standard deviation of 190 MHz over the whole channel was obtained. An average responsivity was 546 V/W with a standard deviation of only 19.2 V/W. A crosstalk was less than -30 dB at frequencies between 3 and 900 MHz and as small as -28 dB even at 1 GHz. The yield of chips available for 1.0 Gb/s operation was as high as 62.5% over 2-in-diameter wafer     

Electrorefraction in GaInAs/InP multiple quantum wellheterostructures

Reports the first absolute measurement of electric-field-induced changes in refractive index in GaInAs quantum well heterostructures. Even for wavelengths as far as 40 meV below the absorption edge, excitonic effects dominate electro-optic phase modulation. This effect close to resonance yields index changes two orders of magnitude larger than in bulk material. The authors find that the size of the index change, its dependence on applied voltage, and its behaviour with wavelength are well described in terms of the quantum confined Stark effect on excitonic absorption     

V-band high-efficiency high-power AlInAs/GaInAs/InP HEMT's

The authors report on the state-of-the-art power performance of InP-based HEMTs (high electron mobility transistors) at 59 GHz. Using a 448-μm-wide HEMT with a gate length of 0.15 μm, an output power of 155 mW with a 4.9-dB gain and a power-added efficiency of 30.1% were obtained. By power-combining two of these HEMTs, an output power of 288 mW with 3.6-dB gain and a power-added efficiency of 20.4% were achieved. This is the highest output power reported with such a high efficiency for InP-based HEMTs, and is comparable to the best results reported for AlGaAs/InGaAs on GaAs pseudomorphic HEMTs at this frequency     

High reliability planar-type GaInAs/InP heterostructure avalanchephotodiodes

High-temperature, long-term life tests of GaInAs/InP heterostructure avalanche photodiodes have been carried out to establish criteria for high reliability photodetectors in 1.55 μm-wavelength optical submarine cable systems. A failure rate of less than 0.2 FIT at 10°C was predicted for the first time with an activation energy of 0.7 eV     

High efficiency GaInAs/InP heterojunction IMPATT diodes

Heterojunction IMPATT diodes make it possible to produce new high conversion efficiency devices, combining a low bandgap semiconductor for the avalanche zone with a large bandgap material for the drift region. In this study, the heterojunction GaInAs/InP which seems particularly attractive is used in various structures. The theoretical predictions of performances are determined by a computer simulation which takes into account the main limitation effects of IMPATT diodes and the influence of particular physical phenomena due to the use of heterojunctions and semiconductors, mainly the influence of injection currents. Potential performances of the proposed structure appear very attractive especially in the millimeter-wave range using a MITATT mode (Mixed-Tunneling-Avalanche-Transit-Time) by combining tunneling current and avalanche multiplication injections.     

Small-junction-area GaInAs/InP pin photodiode with monolithicmicrolens

Reports on a back-illuminated GaInAs/InP pin photodiode with a monolithic microlens fabricated by the authors. The photodiode has both an ultrabroad bandwidth of 18 GHz and a high quantum efficiency of about 84%. It achieves this by using a small pin junction area while maintaining a large fibre alignment tolerance by incorporating an InP microlens. The photodiode capacitance was 20 fF for a junction diameter of approximately 15 μm     

Monolithic integration of a planar embedded InGaAs p-i-n detector with InP depletion-mode FET's

We report the operation of a fully integrated p-i-n FET circuit based on a planar embedded In0.53Ga0.47As p-i-n detector and load resistor with InP depletion-mode FET's. The structure employs selective growth of InGaAs on a semi-insulating InP substrate and selective ion implantation of Si and Be into the InP and InGaAs, respectively. For a 10^-9bit error rate at 1.54 m, the circuit achieves a sensitivity of -34 dBm at 90 Mbit/s and -29.5 dBm at 295 Mbit/s.     

A model-based comparison of AlInAs/GaInAs and InP/GaInAs HBT's: aMonte Carlo study

The high-speed performances of AlInAs/GaInAs and InP/GaInAs heterojunction bipolar transistors (HBTs) are investigated using a one-dimensional self-consistent particle simulator. Optimum alloy compositions for a graded-gap base structure are obtained for both transistors through the tradeoff between the emitter-charging time and base transit time. The saturation velocity in the GaInAs n-type collector is found to be smaller than that in InP, which has been attributed to the diffusion of a large number of hot back-scattered Γ-valley electrons in the GaInAs collector. The difference in the collector transit time in p-type collectors is trivial, since the maximum electron velocity was restricted to below 1.2×10⁸ cm/s due to a strong nonparabolicity effect. The cutoff frequency for the former and the latter are estimated to be 2 and 1.5 times higher, respectively, than for AlGaAs/GaAs HBTs. These results are attributed to a larger bandgap difference between the emitter and base, to yield a high base built-in field, rather than a larger Γ-L band separation energy in the collector to enhance the velocity overshoot effect     

Heterojunction InP/GaInAs phototransistors/bipolar transistorsgrown by MOVPE

Heterojunction InP/GaInAs phototransistors with base terminals have been fabricated by atmospheric pressure metal organic vapour phase epitaxy. When operated as bipolar transistors, the devices exhibit high current gain (>1600) and good junction ideality factors (1.06 for the base/emitter and 1.25 for the base/collector junction). When operated as phototransistors, the devices have large optical gain (>800) at an incident power of 1 μW, at a wavelength of 1.3 μm     

Fabrication of widegap-emitter Schottky-collector transistor using GaInAs/InP

A widegap-emitter transistor with a Schottky collector has been fabricated using n-InP as the emitter, p-GaInAs as the base layer and Ni as the Schottky metallisation. The fabricated transistors show a current gain better than 5 in the common-emitter configuration.     

An InP/InGaAs p-i-n/HBT monolithic transimpedance photoreceiver

A monolithically integrated 1-Gb/s p-i-n/HBT transimpedance photoreceiver is discussed. The optoelectronic integrated circuit (OEIC) was made from metalorganic vapor-phase epitaxy (MOVPE)-grown InP/InGaAs heterostructures and had a transimpedance of 1375 Ω, a sensitivity of -26.1 dBm, >25-dB dynamic range, and a 500-MHz bandwidth