Monolithic GaAlAs/GaAs infrared-to-visible wavelength converter with optical power amplification

A monolithic wavelength converter has been constructed in the GaAlAs alloy system which comprises a wide gap emitter phototransistor and a double heterojunction (DH) light emitting diode (LED) in a bifacial configuration. The liquid phase epitaxy (LPE)-grown structure is capable of efficiently converting IR light with λ < 870 nm into the red spectral range in conjunction with optical power amplification.     

Luminescence of stepped quantum wells in GaAs/GaAlAs and InGaAs/GaAs/GaAlAs structures

Luminescence spectra of doped and undoped GaAs/GaAlAs and InGaAs/GaAs/GaAlAs structures containing several tens of stepped quantum wells (QW) are investigated. The emission bands related to free and bound excitons and impurity states are observed in QW spectra. The luminescence excitation spectra indicate that the relaxation of free excitons to the e1hh1 state proceeds via the exciton mechanism, whereas an independent relaxation of electrons and holes is specific to bound excitons and impurity states. The energy levels for electrons and holes in stepped QWs, calculated in terms of Kane’s model, are compared with the data obtained from the luminescence excitation spectra. The analysis of the relative intensities of emission bands related to e1hh1 excitons and exciton states of higher energy shows that, as the optical excitation intensity increases, the e1hh1 transition is more readily saturated at higher temperature, because the lifetime of excitons increases. Under stronger excitation, the emission band of electron-hole plasma arises and increases in intensity superlinearly. At an excitation level of ～10⁵ W/cm², excitons are screened and the plasma emission band dominates in the QW emission. Nonequilibrium luminescence spectra obtained in a picosecond excitation and recording mode show that the e1hh1 and e2hh2 radiative transitions are 100% polarized in the plane of QWs.     

GaAs/GaAlAs Heterojunction Bipolar Phototransistor for Monolithic Photoreceiver Operating at 140 Mbit/s

The development of optical transmission calls for sensitive and fast optoelectic transducers. With the advent of optical local area networks, hybrid transducers may no longer be appropriate, and monolithic emitters and receivers will be preferred. In this paper, we report on the first monolithic photoreceiver implemented with GaAs-GaAIAs bipolar devices. One phototransistor and two transistors are integrated, together with four resistors on a 0.5x0.5-mm/sup 2/ GaAs chip. The transimpedance receiver has a bandwidth of 80 MHz. SignaI and noise power measurements indicate that for a digital signal at 140 Mbit/s, the minimum detectable power is 1 µW (-30 dBm).     

Optical nonlinearities in a passive GaAs/GaAlAs multiple quantum well strain-induced waveguide

Nonlinear Fabry-Perot switching effects have been observed in a 400 μm long GaAs/GaAlAs MQW strain-induced waveguide resonator. Experimental evidence showing that the mechanism responsible for the switch has a negative coefficient in the refractive index nonlinearity is described; this rules out the possibility that heating could be the cause of the observed switching. However, thermal effects were always present in the background and became more prominent at slow input-power sweep rates. Bistability due to increased absorption has also been observed in a similar nonresonant waveguide structure, at slightly longer wavelengths.     

Monolithic integration of GaAs/AlGaAs double-heterostructure LED's and Si MOSFET's

Fully monolithic integration of interconnected GaAs/Al-GaAs double-heterostructure LED's and Si MOSFET's is demonstrated for the first time. The Si MOSFET's, with a gate length of 5 µm and gate width of 1.6 mm, have almost the same characteristics as those of control devices fabricated on a separate Si wafer. The LED output collected by a microscope lens with a numerical aperture of 0.65 is about 6.5 µW at 100- mA dc current. LED modulation rates up to 27 Mbit/s have been achieved by applying a stream of voltage pulses to the MOSFET gate. The modulation rate is limited by the speed of the MOSFET.     

Monolithic integration of GaAs/AlGaAs LED and Si driver circuit

A GaAs/AlGaAs LED has been monolithically integrated with a Si driver circuit composed of ten MOSFETs. The LED replaces the output pad of a 2- μm design rule, standard Si output buffer circuit, so that the overall area remains the same. By applying a stream of voltage pulses to the input of the driver circuit, the LED output has been modulated at rates exceeding 100 MHz     

Monolithic integration of InAs photodiode and GaAs MESFET

InAs pn diodes were grown in wells pre-etched in GaAs substrates. Despite the large lattice mismatch of 7.2% between GaAs and InAs, good photodiode characteristics were obtained with 77 K resistance area products of 70 Omega cm/sup 2/ and a peak detectivity of 1.25*10/sup 11/ cm square root (Hz)/W at 2.95 mu m wavelength. GaAs MESFETs were fabricated next to the embedded detectors demonstrating for the first time the feasibility of the monolithic integration of InAs photodiodes and GaAs electronic circuits.<>     

Monolithic integration of Si MOSFET's and GaAs MESFET's

Integration of Si MOSFET's and GaAs MESFET's on a monolithic GaAs/Si (MGS) substrate has been demonstrated. The GaAs MESFET's have transconductance of 150 mS/mm for a gate length of 1 µm, and the Si MOSFET's have transconductance of 19 mS/mm for a gate length of 5 µm and an oxide thickness of 800 Å. These characteristics are comparable to those for devices fabricated on separate GaAs and Si substrates.     

GaAs/GaAlAs selective MOCVD epitaxy and planar ion-implantation technique for complex integrated optoelectronic circuit applications

We report on a monolithic integration technique incorporating selective GaAs/GaAlAs optical device epitaxy (based on metalorganic chemical vapor deposition (MOCVD)) and planar ion-implanted GaAs devices, formulated for application to complex integrated optoelectronic circuits. This integration scheme offers fabrication compatibility of epitaxially grown optoelectronic devices with maturing GaAs electronic circuit approaches which require selective multiple implants and small gate geometries. Details of the monolithic integration technique and an example of its application to an optoelectronic transmitter are described.     

Monolithic integration of an AlGaAs/GaAs DH LED with a GaAs FET driver

An AlGaAs/GaAs double heterostructure light emitting diode (LED) and a GaAs field effect transistor (FET) have been monolithically integrated on a GaAs substrate using a combination of liquid phase and molecular beam epitaxies. The electrical isolation between LED and FET has been achieved by inserting a molecular beam-grown high resistivity AlGaAs layer. A linear gate voltage-to-light power transfer characteristic with a 13 ns time constant has been demonstrated.     

Optical activity of Yb in GaAs and low-dimensional GaAs/GaAlAs structures

It is shown that the optical activation of Yb in GaAs and low-dimensional GaAs/GaAlAs structures can be achieved by forming three-component (Yb+S/Se/Te+O) luminescence centers based on the Yb³⁺ ion. A correlation between the characteristics of these centers and the parameters of the chalcogen coactivators is discovered. Oxygen is shown to play a decisive role in transferring the energy of electron-hole pairs to the luminescence centers. Fiz. Tekh. Poluprovodn. 33, 677–679 (June 1999)     

Monolithic integration of optoelectronic devices with reactivematching networks for microwave applications

Microwave impedance matching networks have been, for the first time, monolithically integrated with GaInAs p-i-n photodiodes and GaInAsP buried ridge stripe structure lasers (λ=1.3 μm), both on a semi-insulating InP substrate. The microwave power transfer optical links were compared using matched and unmatched devices. Compared to an unmatched link, an improvement of 11.4 dB at 5.6 GHz (600 MHz bandwidth) is obtained for the totally matched one; this result corresponds quite well to the theoretical prediction (12 dB at 6 GHz)     

Monolithic integration of GaAs photoconductors with a field-effect transistor

A one-stage monolithic integration of a tandem pair of GaAs photoconductors (PCs) with a field-effect transistor (FET) is reported. The PC-FET exhibits a bandwidth in excess of 1 GHz and a gain of 6 dB at midband. A very low noise figure of ~3 dB in the FET is also achieved.     

Monolithic integration of GaAs MESFET and InP/InGaAsP 2*2 optical switch

An optical switching OEIC (optoelectronic integrated circuit), consisting of a GaAs MESFET and an InP/InGaAsP 2*2 buried waveguide optical switch, is reported for the first time. Fully monolithic integration is obtained by heteroepitaxial GaAs-on-InP growth and photolithographical interconnection. The combined OEIC allows switching voltages of about 1 V with an extinction ratio of -6 dB.<>     

Base-emitter diffusion capacitance in GaAlAs/GaAs HBTs

The voltage dependence of the base-emitter diffusion capacitance in a single heterojunction GaAlAs/GaAs HBT is discussed. It is found that conventional transistor capacitance models are not accurate for these devices. An empirical expression is given which may be used to model this diffusion capacitance.<>     

Monolithic optoelectronic circuit design and fabrication byepitaxial growth on commercial VLSI GaAs MESFET's

A technique for realizing large-scale monolithic OEIC's, which involves epitaxially growing GaAs-based heterostructures on fully metallized commercial VLSI GaAs MESFET integrated circuits, has recently been reported. In the initial work the circuits and LED's occupied distinct halves of a chip, the dielectric growth window was wet-etched after circuit fabrication, and the LED's required both n and p ohmic contacts to be formed after epitaxial growth. In this letter we report the use of standard foundry process etches to open dielectric growth windows intermixed with circuitry and the growth of n-side-down LED's on a source/drain ion-implanted n⁺ region serving as the n ohmic contact. A winner-take-all neural circuit is demonstrated using these advances, which are important steps toward realizing higher levels of circuit integration     

Hot phonons and instabilities in GaAs/GaAlAs structures

We report experimental observations concerning high field parallel transport in GaAs/GaAlAs quantum-well structures comparing degenerate and non-degenerate material. Hot electron photoluminescence measurements show hot-phonon reduction of the energy relaxation rates in degenerate material as compared with that in non-degenerate material in agreement with a simple model of transport involving hot phonon effects. The latter predicts a reduction in drift velocity at high fields compared with that in bulk material and this is observed in our specimens. Hot phonons are shown to inhibit instabilities. Non degenerate samples exhibit current instabilities much more readily than degenerate material. In the latter, the hot phonon reduction in drift velocity will tend to inhibit NDR via real space transfer or via intervalley transfer.     

Resolution Characteristics of GaAs/GaAlAs Transmission Photocathode

The reolution characteristic of GaAs/GaAlAs trransmission photocathode is an important parameter in third generation intensifiers.The modulation transfer function of GaAs/GaAlAs transmission photocathode is derived from a simple two-dimensional diffusion equation.The theoretical resolution characteristic of a 2 μm thick GaAs/GaAlAs transmission photocathode is calculated.The relationship between resolution and parameters in GaAs/GaAlAs transmission photocathode is discussed.A conclusion is shown that one can design the GaAs/GaAlAs transmission photocathode for maximum quantum efficiency,since the sacrifice in the resolution doesn‘t limit system performances.     

GaAs/GaAlAs透射式光电阴极的分辨力特性分析

Ｇａ Ａｓ／ Ｇａ Ａｌ Ａｓ 透射式光电阴极的分辨力是第３ 代微光像增强器的重要参数之一。从简化的二维扩散方程推导了 Ｇａ Ａｓ／ Ｇａ Ａｌ Ａｓ 透射式阴极的调制传递函数（ Ｆｍ ,ｔ） ,计算了２ μｍ 厚 Ｇａ Ａｓ 阴极层的 Ｇａ Ａｓ／ Ｇａ Ａｌ Ａｓ 透射阴极的理论分辨力特性曲线,并讨论了它与若干参数的关系。据此得出在设计 Ｇａ Ａｓ／ Ｇａ Ａｌ Ａｓ 透射式光电阴极时应主要考虑最大量子效率,分辨力的损失并不限制系统的性能。     

Monolithic integration of surge protection diodes into low-noise GaAs MESFET's

For use in practical equipment, GaAs MESFET's need Schottky gates with high energy tolerance against electrostatic discharge. This paper describes the design and fabrication technology related to the monolithic integration of protective diodes into low-noise GaAs MESFET's. A new diode structure, the grooved sidewall junction diode (GSJD), is proposed which is well suited for suppressing deterioration of the FET's RF performance. The GSJD was successfully integrated into the dual-gate low-noise GaAs FET for use in a UHF TV tuner. High energy tolerance of 50 erg was obtained in the device with a noise figure of 1.2 dB at 1 GHz.