I. Gyuro

Analysis of gate leakage on MOVPE grown InAlAs/InGaAs-HFET

The leakage of reverse biased Schottky gates on lattice matched InAIAs/InGaAs HFET grown by MOVPE on s.i. InP subtsrates is adressed. The contribution of (i) (thermionic-) field emission across the Schottky barrier (ii) generation-recombination in the space charge region and (iii) impact ionization with subsequent hole tunneling are identified by means of their temperature dependence. Taking the overall importance of the gate to channel potential into account we will show that the leakage in biased HFET with a doping level ND ≪ 4*1018cm-3 is dominated by impact ionization.

Photoluminescence study of implantation‐induced intermixing of In0.53Ga0.47As/InP single quantum wells by argon ions

We have performed systematical investigations of intermixing effects in In0.53Ga0.47As/InP single quantum wells induced by 30‐keV Ar+‐ion beam implantation with doses ranging from 1012 to 1014 cm−2 and a subsequent rapid thermal annealing (RTA) at temperatures between 600 and 900 °C. After implantation and RTA at 600 °C we observe a significant increase of the photoluminescence emission energy of about 60 meV in comparison with unimplanted heterostructures, indicating that the intermixing is determined by implantation. For RTA above 850 °C, in contrast, the energetic shifts up to 200 meV observed for the implanted samples are similar to the shift in unimplanted samples, indicating a predominant contribution of thermal interdiffusion. The significant decrease of Ga concentration after interdiffusion is confirmed quantitatively by Raman measurements.

De-embedding of on-wafer lightwave measurements performed on a monolithic 10 Gb/s InP receiver-oeic

Small-and large-signal measurements on 10 Gb/s monolithic receiver-OEICs of straight forward termination type consisting of InGaAs/InP pin-photodiodes and InAIAs/InGaAs/InP HEMTs are presented. On-wafer characterization of both, isolated devices and OEICs is perforrned using deembedding procedures, which allow for comparison of theoretical and experimental performance.

Gain-modulated second order distributed feedback gratings fabricated by maskless focused ion beam implantation in GaInAsP heterostructures

Second order periodic gain modulation in GaInAsP laser structures has been realized by maskless focused ion beam implantation. The structures were implanted with Ga^+-ions at an ion energy of 130 keV and line doses between 3x10^6/cm to 7x10^8/cm. The periodicity of the gratings was designed for 77 K (460 nm period) and room temperature (500 nm period). Using optical pumping we have observed monomode emission spectra due to gain modulation at wavelengths of 1.44 @mm (77 K) and 1.56 @mm (300 K), respectively. Implanted structures show laser operation up to annealing temperatures of 700 ^oC. This indicates that maskless patterning by focused ion beams is compatible with epitaxial overgrowth.

Optical Investigations of the Sidewall Recombination in Wet Etched InGaAs/InP-Wires

We have investigated the optical properties of wet chemically etched InP/InGaAs-wires with widths between 100 nm and 10 µm for a wide range of excitation densities and energies. We observe that the non radiative recombination centers at the etched sidewalls can be saturated already at moderate excitation densities of 100 W/cm2. Avoiding saturation effects we obtain a surprisingly large sidewall recombination velocity of 107 cm/s at 77 K. The comparison of luminescence measurements at excitation energies above and below the InP band gap energy shows, that the non radiative recombination centers are located in the InGaAs quantum well.

Metalorganic vapor phase epitaxial grown heterointerfaces to GaInP with group-III and group-V exchange

Metalorganic vapor phase epitaxial grown heterointerfaces to Ga x In 1-x P (x≃0.5) are studied. Abruptness optimization is carried out by means of a gas switching procedure using a hydrogen purge between AsH 3 and PH 3 stabilization. X-ray analysis and scanning transmission electron microscopy are used to provide detailed information about interlayers and Ga-segregation from a fitting of simulated to experimental rocking curves in comparison to atomic-number contrast images. InGaAs/InAlAs heterostructure field-effect transistors on an InP-substrate are prepared incorporating a highly strained Ga 0.5 In 0.5 P spacer layer. Excellent transport data (μ H,300K >11000 cm 2 /V.s) are proving that despite the strain and segregation effect in the strained ternary the lower interface at the channel/spacer transition is highly abrupt

Comparison of the sidewall recombination in dry and wet etched InGaAs/InP wires

Abstract We have investigated the influence of the sidewall recombination on the photoluminescence intensity of wet and dry etched InGaAs/InP wires with widths between 60 nm and 10 μm for a wide range of excitation densities. While we obtain a large sidewall recombination velocity in the range of 10 7 cm/sec at low excitation density, the decay of the emission intensity with decreasing wire width is completely suppressed at higher excitation density due to the saturation of nonradiative recombination centers. Varying the bias voltage of the dry etching process from 80 V up to 300 V we observe a significant increase of the sidewall recombination of dry etched structures at ion energies above 200 eV.

On-wafer characterization, modelling, and optimization of InP-based HEMTs, PIN-photodiodes and monolithic receiver-OEICs for fiber-optic communication

The authors present results achieved with receiver OEICs (optoelectronic integrated circuits) consisting of InGaAs PIN-photodiodes and InAlAs/InGaAs HEMTs (high electron mobility transistors) grown by low-pressure MOVPE (metalorganic vapor phase epitaxy) on semi-insulating InP substrates. Both devices were realized on the same wafer. A 3-dB bandwidth of 1.6 GHz and an open eye at 3.0 Gb/s NRZ modulation of the monolithically integrated photoreceiver were obtained by on-wafer characterization.<<ETX>>

Evidence of oxygen in undoped InAlAs MOVPE layers

InAlAs layers lattice matched to InP were grown by LP-MOVPE (low-pressure metal-organic vapor-phase epitaxy). The layers were characterized with respect to deep levels by C-V, SIMS (secondary ion mass spectroscopy) and photocapacitance measurements. Oxygen was definitely found by SIMS measurements and temperature-dependent C-V measurements as the most important defect impurity stemming from the epitaxial sources. The activation energy was determined to Delta E/sub T/=85 meV. The concentration strongly depends on the growth condition. High growth temperatures lead to low concentrations of oxygen and silicon. The lower limit is given by the quality of the precursors, the gas purifying system, and the growth conditions. Four deeper levels have been found with low concentrations with no significant influence on the layer properties.<<ETX>>

Optical analysis of wet chemically etched InGaAs/InP wires

Abstract We have investigated the influence of the sidewall recombination on the photoluminescence intensity of wet etched InGaAs/InP wires. We observe a strong influence of the sidewall recombination for low excitation powers (≈10W/cm2) independent of the particular etchant used. By using an Na2S-passivation layer the nonradiative sidewall recombination can be suppressed completely.