10-gb/s operation of an In/sub 0.53/Ga/sub 0.47/As p-i-n photodiode on metamorphic InGaP buffered semi-insulating GaAs substrate

The SONET OC-192 receiving performance of In/sub 0.53/Ga/sub 0.47/As p-i-n photodiode grown on linearly graded metamorphic In/sub x/Ga/sub 1-x/P buffered GaAs substrate is reported. With a low-cost TO-46 package, such a device exhibits a frequency bandwidth up to 8 GHz, a bit-error rate (BER) of 10/sup -9/ at 10 Gb/s, a sensitivity of -17.8 dBm, and a noise equivalent power of 3.4/spl times/10/sup -15/ W/Hz/sup 1/2/ owing to its ultralow dark current of 3.6/spl times/10/sup -7/ A/cm/sup 2/. Eye diagram analysis at 10 Gb/s without transimpedance amplification reveals a statistically distributed Q-factor of 8.21, corresponding to a minimum BER of 1.1/spl times/10/sup -16/ at receiving power of -6 dBm.     

Thermal resistance of metamorphic InP-based HBTs on GaAs substrates using a linearly graded In/sub x/Ga/sub 1-x/P metamorphic buffer

Thermal properties of metamorphic InP-InGaAs heterojunction bipolar transistors (HBTs) on GaAs substrates using a linearly graded InGaP buffer have been investigated. Compared to the widely used InAlAs metamorphic buffer, InGaP offers better thermal properties resulting in a much smaller thermal resistance for the metamorphic HBTs (MHBTs). Theoretical calculations of the thermal resistance of devices have been made based on a simple constant heat-spreading model, and the results are shown to be consistent with experimental results. It has been made clear that the smaller thermal resistance measured from the MHBTs using a linearly graded InGaP buffer is due to the small bowing parameters and high thermal conductivity of the binary endpoints. Although the use of InGaP as a buffer may slightly degrade the devices thermal properties compared to one using InP directly on GaAs substrate, it gives more freedom to the growth optimization of metamorphic buffer by using compositional grading. With regards to the thermal conductivity and flexible growth optimization, InGaP metamorphic buffer could be considered as an important alternative to the existing InAlAs and InP schemes.     

Metal-semiconductor-metal photodetector on p-type In/sub 0.53/Ga/sub 0.47/As

An MSM Schottky barrier photodetector based on p-type In/sub 0.53/Ga/sub 0.47/As suitable for detection in the 0.8-1.7 wavelength range is reported. Aluminium metallisation was used. The large area devices exhibited responsivity of about 0.4 A/W at 1.3 mu m and tau /sub on/>     

High-performance, metamorphic In/sub x/Ga/sub 1-x/As tunnel diodes grown by molecular beam epitaxy

Thin In/sub x/Ga/sub 1-x/As tunnel junction diodes having compositions from x=0.53 to 0.75 that span a range of bandgap energies from 0.74 to 0.55 eV, were grown on InP and metamorphic, step-graded In/sub x/Al/sub 1-x/As/InP substrates using molecular beam epitaxy and evaluated in the context of thermophotovoltaic (TPV) applications. Both carbon and beryllium were investigated as acceptor dopants. Metamorphic tunnel diodes with a bandgap of 0.60 eV (x=0.69) using carbon acceptor doping displayed highest peak current densities, in excess of 5900 A/cm/sup 2/ at a peak voltage of 0.31 V, within a 200 /spl Aring/ total thickness tunnel junction. Identically doped lattice-matched tunnel diodes with a bandgap of 0.74 eV exhibited lower peak current densities of approximately 2200 A/cm/sup 2/ at a higher peak voltage of 0.36 V, consistent with the theoretical bandgap dependence expected for ideal tunnel diodes. Specific resistivities of the 0.60 eV bandgap devices were in the mid-10/sup -5/ /spl Omega/-cm/sup 2/ range. Together with their 200 /spl Aring/ total thickness, the electrical results make these tunnel junctions promising for TPV applications where low-resistance, thin metamorphic tunnel junctions are desired.     

MESFET-like transferred-electron devices in In/sub 0.53/Ga/sub 0.47/As

In/sub 0.53/Ga/sub 0.47/As transferred-electron devices with Schottky-gate electrodes were fabricated. These devices can be used in optoelectronic circuits on InP or as millimetre wave oscillators. For the realisation of the gate electrode several enhancement layers were tested to increase the Schottky barrier height on In/sub 0.53/Ga/sub 0.47/As. The triggering of single dipole domains in the device was demonstrated.<>     

In0.53Ga0.47As p-i-n photodiodes for long-wavelength fibre-optic systems

We describe p-i-n photodiodes fabricated from In0.53Ga0.47As grown lattice-matched on InP substrates. These diodes exhibit low junction capacitance (C<1 pF at 20 V reverse bias), low dark current (?10 nA), high break-down voltage (110 V) and wide photoresponse extending beyond 1.7 ?m.     

Threshold voltage of submicron Ga/sub 0.47/In/sub 0.53/As HIGFETs

Presents threshold voltage data for Al/sub 0.48/In/sub 0.52/As/Ga/sub 0.47/In/sub 0.53/As/InP heterostructure insulated gate FETs (HIGFETs) with gate lengths from 1.2 mu m to 0.4 mu m. The refractory-gate, self-aligned fabrication process was applied to MBE-grown structures with 300 AA Ga/sub 0.47/In/sub 0.53/As channels and semi-insulating superlattice buffers to achieve sharp pinchoff with excellent threshold uniformity. HIGFETs with L/sub g/=1.2 mu m showed a threshold voltage of -0.076+or-0.019 V, making them well-suited to application in direct-coupled FET logic (DCFL) circuits.<>     

High-performance In/sub 0.53/Ga/sub 0.47/As thermophotovoltaic devices grown by solid source molecular beam epitaxy

In/sub 0.53/Ga/sub 0.47/As-based monolithic interconnected modules (MIMs) of thermophotovoltaic (TPV) devices lattice-matched to InP were grown by solid source molecular beam epitaxy. The MIM device consisted of ten individual In/sub 0.53/Ga/sub 0.47/As TPV cells connected in series on an InP substrate. An open-circuit voltage (V/sub oc/) of 4.82 V, short-circuit current density (J/sub sc/) of 1.03 A/cm/sup 2/ and fill factor of /spl sim/73% were achieved for a ten-junction MIM with a bandgap of 0.74 eV under high intensity white light illumination. Device performance uniformity was better than 1.5% across a full 2-in InP wafer. The V/sub oc/ and J/sub sc/ values are the highest yet reported for 0.74-eV band gap n-p-n MIM devices.     

平面型铟镓砷线列探测器的制备及伏安特性研究

通过闭管锌扩散制备了256元平面型铟镓砷(In0.53Ga0.47As)线列探测器,室温下焦平面平均峰值探测率为5.79×1011cmHz1/2W-1,不均匀性为31%,平均峰值响应率为0.33 A/W.并且通过拟合其伏安曲线得到了器件的理想因子和串联电阻,基于这两个相互独立的参数可以对器件不同区域的性质加以考查,结果表明器件材料具有较好的均匀性,而器件的欧姆接触电阻偏大,且不均匀性达到39%,为工艺的改进提供了重要依据.     

Ga0.47In0.53As field-effect transistors with a lattice-mismatched reduced leakage current GaAs gate

A lattice-mismatched GaAs gate Ga0.47In0.47As field-effect transistor (LMG-FET) with significantly reduced reverse gate leakage current is reported. The mechanism responsible for this reduction by over two orders of magnitude over previous work has been identified; it is attributed to the confinement of misfit dislocations originating at the GaAs/InGaAs interface. The LMG-FET had a gate leakage current of 0.48 ?A at ? V, and an extrinsic DC transconductance of 104 mS/ mm for a 1.4 ?m gate length and 240 ?m gate width. Further refinements in crystal growth should lead to even lower values of leakage current, making this technology attractive for high-speed logic, as well as lightwave optoelectronic integration.     

Field dependence of impact ionization coefficients in In/sub 0.53/Ga/sub 0.47/As

Electron and hole ionization coefficients in In/sub 0.53/Ga/sub 0.47/As are deduced from mixed carrier avalanche photomultiplication measurements on a series of p-i-n diode layers, eliminating other effects that can lead to an increase in photocurrent with reverse bias. Low field ionization is observed for electrons but not for holes, resulting in a larger ratio of ionization coefficients, even at moderately high electric fields than previously reported. The measured ionization coefficients are marginally lower than those of GaAs for fields above 250 kVcm/sup -1/, supporting reports of slightly higher avalanche breakdown voltages in In/sub 0.53/Ga/sub 0.47/As than in GaAs p-i-n diodes.     

High-performance Al/sub 0.48/In/sub 0.52/As/Ga/sub 0.47/In/sub 0.53/As MSM-HEMT receiver OEIC grown by MOCVD on patterned InP substrates

Reports the first demonstration of a new long-wavelength receiver OEIC comprising an AlInAs/GaInAs MSM detector and an AlInAs/GaInAs HEMT preamplifier. The layer structure was grown by LP-MOCVD on patterned InP substrates, which allowed independent optimisation of the MSM detector and HEMT preamplifier. The MSM detector showed the lowest leakage current yet reported and the HEMT exhibited a transconductance of 260 mS/mm. An excellent receiver response to 1.7 Gbit/s NRZ signals has been obtained.<>     

A novel InGaP/Al/sub x/Ga/sub 1-x/As/GaAs CEHBT

A new and interesting InGaP/Al/sub x/Ga/sub 1-x/As/GaAs composite-emitter heterojunction bipolar transistor (CEHBT) is fabricated and studied. Based on the insertion of a compositionally linear graded Al/sub x/Ga/sub 1-x/As layer, a near-continuous conduction band structure between the InGaP emitter and the GaAs base is developed. Simulation results reveal that a potential spike at the emitter/base heterointerface is completely eliminated. Experimental results show that the CEHBT exhibits good dc performances with dc current gain of 280 and greater than unity at collector current densities of J/sub C/=21kA/cm/sup 2/ and 2.70/spl times/10/sup -5/ A/cm/sup 2/, respectively. A small collector/emitter offset voltage /spl Delta/V/sub CE/ of 80 meV is also obtained. The studied CEHBT exhibits transistor action under an extremely low collector current density (2.7/spl times/10/sup -5/ A/cm/sup 2/) and useful current gains over nine decades of magnitude of collector current density. In microwave characteristics, the unity current gain cutoff frequency f/sub T/=43.2GHz and the maximum oscillation frequency f/sub max/=35.1GHz are achieved for a 3/spl times/20 /spl mu/m/sup 2/ device. Consequently, the studied device shows promise for low supply voltage and low-power circuit applications.     

Performance improvement in tensile-strained In/sub 0.5/Al/sub 0.5/As/In/sub x/Ga/sub 1-x/As/In/sub 0.5/Al/sub 0.5/As metamorphic HEMT

This paper proposes a In/sub 0.5/Al/sub 0.5/As/In/sub x/Ga/sub 1-x/As/In/sub 0.5/Al/sub 0.5/As (x=0.3-0.5-0.3) metamorphic high-electron mobility transistor with tensile-strained channel. The tensile-strained channel structure exhibits significant improvements in dc and RF characteristics, including extrinsic transconductance, current driving capability, thermal stability, unity-gain cutoff frequency, maximum oscillation frequency, output power, power gain, and power added efficiency.     

Femtosecond optical response of low temperature grown In0.53Ga0.47As

A femtosecond, tunable color center laser was used to conduct degenerate pump-probe transmission spectroscopy of thin film low temperature grown molecular beam epitaxy In_0.53Ga_0.47As samples. Low temperature molecular beam epitaxy In_0.53Ga_0.47As exhibits a growth-temperature dependent femtosecond optical response when probed near the conduction band edge. Below T_g=250°C, the optical response time of the material is subpicosecond in duration, and we observed induced absorption, which we suggest is due to the formation of a quasi-“three-level system”.     

Integrated In0.53Ga0.47As p-i-n f.e.t. photoreceiver

The first operation of an integrated p-i-n-photodiode/f.e.t.-amplifier on a single wafer of In0.53Ga0.47As grown lattice matched to an InP substrate is reported.     

Ohmic contacts on p-type Ga0.47In0.53As/InP

Ohmic contacts of Au and Ag based Zn containing alloys on p-type Ga_0.47In_0.53As have been studied using intermediate layers of Ti and Ni, respectively. Low specific contact resistance in the order of 10⁻⁵ Ωcm² are achieved. In case of AuZn alloy, the Ti intermediate metal layer causes higher contact resistances together with a worse contact morphology in contrast to Ni intermediate layers. However for AgZn contacts Ti adherent layers improve the contact resistances, especially for lower alloying temperatures. Moreover these contacts exhibit significant smoother interfaces as revealed by TEM micrographs. Thus AgZn contacts apply best to low resistive contacting of very thin p-layers forming e.g. the base of a ballistic device.     

InP衬底AlAs/In0.53Ga0.47As RTD的研制

报道了InP衬底AlAs/In0.53Ga0.47As/AlAs两垒一阱结构共振隧穿二极管(RTD)器件的研制.结构材料由分子束外延制备,衬底片为(001)半绝缘InP单晶片,器件制作选用台面结构.测得室温下的峰值电流密度为1.06×105 A/cm2,峰-谷电流比为7.4,是国内报道的首例InP材料体系RTD器件.     

InP衬底AlAs/In0.53Ga0.47As RTD的研制

报道了InP衬底AlAs/In0.53Ga0.47As/AlAs两垒一阱结构共振隧穿二极管(RTD)器件的研制.结构材料由分子束外延制备,衬底片为(001)半绝缘InP单晶片,器件制作选用台面结构.测得室温下的峰值电流密度为1.06×105 A/cm2,峰-谷电流比为7.4,是国内报道的首例InP材料体系RTD器件.     

Ga0.47In0.53As JFETs and MESFETs with OM-VPE-grown GaAs surface layers

Ga0.47In0.53As JFETs and MESFETs have been fabricated with a lattice-mismatched GaAs layer under the gate. The GaAs could be grown with good electrical and crystallo-graphic quality in spite of the large lattice mismatch by an OM-VPE process. Pn, Np and Schottky diodes were fabricated and applied to n-GaInAs FET channels. Both types of devices exhibited high transconductances of about 100 mS/mm.