Kink-free AlInAs/GaInAs/InP HEMTs grown by molecular beam epitaxy

Kink-free AlInAs/GaInAs/InP HEMTs have been fabricated from an MBE structure grown under normal growth condition. Devices with 1 mu m gate-length exhibit an extrinsic transconductance of 450 mS/mm and a maximum drain current of 600 mA/mm which represent the best results for 1 mu m gate devices. The DC output conductance shows no kink over the entire gate bias range. The elimination of the kink is attributed to the high quality AlInAs buffer layer and a low mismatch between the AlInAs buffer layer and InP substrate.<>     

Monolithic integration of fully ion-implanted lateral GaInAs pin detector/InP JFET amplifier for 1.3-1.55 mu m optical receivers

An optical receiver front-end consisting of a lateral interdigitated GaInAs pin detector integrated with an InP JFET amplifier has been fabricated. This lateral detector structure simplifies the GaInAs material growth requirement to a single layer and provides low capacitance. A quasiplanar approach has been developed in conjunction with a two-level metallisation interconnect scheme. An optical sensitivity of -29 dBm was measured at 560 Mbit/s and 1.3 mu m wavelength.<>     

Double-heterojunction bipolar transistors in InP/GaInAs grown by metal organic chemical vapour deposition

Double-heterojunction bipolar transistor structures in InP/GaInAs have been grown by low-pressure metal organic chemical vapour deposition. Good control of the Zn dopant in the GaInAs base layer was achieved, and devices with current gains up to 300 at current densities of 1.4kA/cm2 have been demonstrated.     

HEMT millimetre wave monolithic amplifier on InP

A single-stage lossy match cascode amplifier was realised on InP substrate. The amplifier has a small-signal gain of 17+or-1 dB over the frequency range 24-40 GHz. The active device is a 0.25 mu m triangular gate GaInAs/AlInAs HEMT lattice matched to InP.<>     

Fabrication and characterisation of long-wavelength, GaInAs/AlGaInAs/InP modified-MQW lasers

Room-temperature operation of GaInAs/AlGaInAs/InP M-MQW lasers grown by low-pressure MOVPE is described for the first time. Threshold current densities were as low as 1.9 kA cm/sup -2/ with emission wavelengths of 1.59 mu m.<>     

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.<>     

94 GHz InP MMIC five-section distributed amplifier

A single-stage 94 GHz InP MMIC amplifier with 6.4 dB gain at 94 GHz has been developed, which is the highest-frequency MMIC amplifier reported to date. Lattice-matched GaInAs/AlInAs HEMTs with 0.1 mu m mushroom gates were the active devices. The CPW MMIC chip dimensions are 500 mu m*670 mu m.<>     

High speed non-selfaligned InP/InGaAs Npn heterojunction bipolar transistor grown by low pressure metal organic vapour phase epitaxy

Lattice matched GaInAs/InP Npn heterojunction bipolar transistors (HBTs) have been grown by lower pressure metal organic vapour phase epitaxy (MOVPE) and precessed with non-selfaligned fabrication techniques. The transistors exhibit a cutoff frequency of 60 GHz and maximum oscillation frequency of 32 GHz which are the highest values reported to date for GaInAs/InP HBTs grown by MOVPE.<>     

Planar-junction, top-illuminated GaInAs/InP pin photodiode with bandwidth of 25 GHz

A top-illuminated GaInAs/InP pin photodiode has been produced in a planar-junction configuration, which combines high reliability (no change in dark current over 4700 h at 175 degrees C) with the widest bandwidth (25 GHz), and highest quantum efficiency (80% at 1.55 mu m), yet reported for this type of device.<>     

Monolithic PIN-HEMT receiver with internal equaliser for long-wavelength fibre optic communications

An optical receiver, in which a GaInAs PIN photodiode, an AlInAs/GaInAs HEMT high impedance amplifier and even an equaliser were integrated monolithically on an InP substrate, has been fabricated. An optical sensitivity of -30.4 dBm was obtained at 1.2 Gbit/s and 1.3 mu m wavelength.<>     

Abrupt Delta-Doped InP/GaInAs/InP DHBTs With 0.45-$muhbox{m}$ -Wide T-Shaped Emitter Contacts

An abrupt pulse-doped InP/GaInAs/InP double heterojunction bipolar transistor having a 0.45- $muhbox{m}$-wide T-shaped emitter metal is reported. These two promising technologies for sub-100-nm emitters were previously demonstrated only for 1- $muhbox{m}$ emitters. The device exhibited typical dc and microwave performance to 0.5- $muhbox{m}$ emitter devices.      

Excess noise design of InP/GaInAsP/GaInAs avalanche photodiodes

An InP/GaInAsP/GaInAs avalanche photodiode (APD) with separate absorption and multiplication (SAM) regions has been designed taking into account the excess noise generated in GaInAsP and GaInAs. The multiplication factor dependence of the excess noise factorFhas been calculated using realistic electron and hole ionization rates in InP, GaInAsP, and GaInAs, assuming that the avalanche multiplication occurs not only in InP but in GaInAsP and GaInAs. The calculatedFvalues have been compared to the experimental ones measured on a planar-type InP/GaInAsP/GaInAs APD for illumination at a wavelength of 1.3 μm. It has been found the the calculated excess noise agrees very well with the experimental measurements. The limited ranges of device parameters in which the conditions of minimal excess noise, tunneling current, and charge pile-up are satisfied have been obtained. We conclude that the excess noise generated in GaInAsP and GaInAs should be considered in a practical device design.     

High-temperature (T=490 K) operation of 5.8 /spl mu/m quantum cascade lasers with InP/GaInAs waveguides

5.8 /spl mu/m Ga/sub 0.4/In/sub 0.6/As/Al/sub 0.56/In/sub 0.44/As strain-compensated quantum-cascade lasers with InP and GaInAs cladding layers using solid-source molecular-beam epitaxy have been fabricated. Low threshold current densities and high-temperature operation of uncoated devices, with a record value of 490 K, have been achieved in pulsed mode.     

GaInAs/InP quantum wires grown by metalorganic vapor phase epitaxy on V-grooved InP substrates

A single nominally lattice matched GaInAs quantum well (QW)/quantum wire (QWR) structure was grown by metalorganic vapor phase epitaxy (MOVPE) in V-grooved InP substrates. Different Si0₂ etch masks with opening widths from 2 μm down to 200 nm (for application as second order DFB grating) were defined by optical and electron beam lithography. A damage-reduced wet chemical etching process enables the growth of the GaInAs QWs/QWRs without any InP buffer layer. In low temperature photoluminescence we found improved intensity for all wire structures prepared by this etching technique. A reduction of the period and opening width of the V-groove etch mask resulted in a optimized luminescence intensity ratio between QW and QWR. Decay times from time resolved luminescence measurements were compared to the decay times of wet or dry etched mesa wires before and after regrowth. The good optical properties of the GaInAs QWRs are encouraging for future application as a QWR-laser device.     

Observation of field-induced refractive index variation in quantum box structure

An electric-field-induced refractive index variation in a GaInAs/InP five-layered quantum box structure was observed for the first time. The wavelength dependence of the refractive index variation was measured to confirm the quantum box effect. The size of the GaInAs/InP quantum box was estimated to be (22-30 nm)/sup 2/ with the thickness of 7.5 nm. from the spectral property of the field-induced refractive index variation. The maximum value of the refractive index variation in the quantum box was evaluated to be 7% around 1.52 mu m wavelength at an applied electric field of 8*10/sup 4/ V/Cm.<>     

a-Si:H Schottky gate on n-GaInAs

The metal Schottky contact leads to low barrier heights on small-gap (<1 eV) semiconductors. This is the case of the n-type GaInAs material matched to InP where this barrier does not exceed 0.3 eV. We have found an original method to improve this result considerably by using a deposition of an amorphous semiconductor a-Si or a-Si: H. A Pt metal acts as the Schottky contact on the amorphous layer. The device behaves like a heterostructure of a high-gap (amorphous layer: Eg?1.8 eV) on a small-gap (GaInAs:0.75 eV) material. The Schottky-barrier height (0.8 eV) is greater than the GaInAs bandgap (0.75 eV). The reverse current is very low: 20 nA at 1 V reverse voltage for a 0.6 mm diode diameter. An FET using a-Si: H as a gate realised on a GaInAs layer shows a good electrical characteristic.     

Flip-chip planar GaInAs/InP p-i-n photodiodes-fabrication andcharacteristics

New flip-chip planar GaInAs/InP p-i-n photodiodes have been fabricated as an array. We describe the structure of the photodiode, the design of a microlens, the fabrication processes, characteristics, and the optical fiber-coupled modules. This photodiode satisfied the requirements for a small junction capacitance and low dark current, good optical fiber coupling, and easy fabrication. We obtained a low dark current with good reproducibility by using two layer polyimide and SiN passivation films. A microlens with a 50 μm φ to 120 μm φ aperture could easily be fabricated with an InP-substrate. By electroplating, flip-chip metal bumps were directly formed on the active region of the photodiode for the first time     

Refractive index change of GaInAs/InP disordered superlattice waveguide

The refractive index changes of disordered superlattice waveguides were measured and evaluated. A GaInAs/InP superlattice structure grown by gas-source molecular beam epitaxy (MBE) was disordered by the Si/sub 3/N/sub 4/ cap annealing method. The measurement of the wavelength response of a Bragg grating waveguide shows that the refractive indexes of the disordered region vary gradually in accordance with the development of partial disordering. Maximum refractive index changes were -1.1*10/sup -2/ for the transverse electric mode and +6.7*10/sup -3/ for the transverse magnetic mode at 1.5 mu m wavelength.<>     

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     

Double heterostructure Ga0.47In0.53As MESFETs by MBE

Ga0.47In0.53As MESFETs have been fabricated on InP substrates. The low barrier height of Ga0.47In0.53As (0.20 eV) which makes simple GaInAs MESFETs at this composition impractical, has been overcome by using thin Al0.48In0.52As layers between gate metal and GaInAs active layers. Al0.48In0.52As has also been exploited in the form of buffer layers. The double heterostructure FET wafers with single crystal Al gate metal were grown by molecular beam epitaxy (MBE). The 2.75 µm gate length MESFETs showed d.c. transconductance gm= 57 mS mm^-1in spite of nonoptimized dimensions.