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A novel method for fabricating photonic crystal membrane light emitting diodes is presented. The device employs a transverse diode structure and injects carriers laterally through a photonic crystal patterned at the p-n junction within a membrane. Details of the fabrication process as well as electrical and optical characteristics of the devices are presented.

Dielectric layers are often employed as etch masks for mesa and trench structures during vertical-cavity surface-emitting laser (VCSEL) fabrication. The removal of these mask layers by reactive ion etching results in unavoidable exposure of the top laser facet to sputtering. This sputtering is experimentally shown to impact the device performance. After a thickness of less than a quarter wavelength (∼60nm) has been removed, the VCSELs are no longer able to achieve lasing threshold. Simulation indicates that the reason for this is a decrease in quality factor by more than an order of magnitude. Consistent with this explanation is that the damage can be partially repaired (allowing laser oscillation) by depositing SiO2 to compensate for the missing semiconductor material.

Depth profile analysis by high-resolution secondary ion mass spectrometry (SIMS) can accurately determine C and Si concentrations within monolithic reflectors of vertical cavity surface-emitting lasers (VCSELs). These SIMS depth profiles are quantified to atomic concentrations using relative sensitivity factors and calibration standards, and are correlated to the laser characteristics. We compare the light output versus current and voltage of a conventional oxide-confined VCSEL with a self-pulsating VCSEL. We show that SIMS depth profiling of VCSELs can be useful as a diagnostic method for VCSEL epitaxial wafers, and that the doping level of oxide aperture layers can dramatically impact the device performance.

The authors have investigated the properties of GaAsSb/InGaAs type-II bilayer quantum well structures grown by molecule beam epitaxy for use in long-wavelength lasers on GaAs substrates. Structures with layer, strains and thicknesses designed to be thermodynamically stable against dislocation formation exhibit room-temperature photoluminescence at wavelengths as long as 1.43 {mu}m. The photoluminescence emission wavelength is significantly affected by growth temperature and the sequence of layer growth (InGaAs/GaAsSb vs GaAsSb/InGaAs), suggesting that Sb and/or In segregation results in non-ideal interfaces under certain growth conditions. At low injection currents, double heterostructure lasers with GaAsSb/InGaAs bilayer quantum well active regions display electroluminescence at wavelengths comparable to those obtained in photoluminescence, but at higher currents the electroluminescence shifts to shorter wavelengths. Lasers have been obtained with threshold current densities as low as 120 A/cm{sup 2} at 1.17 {mu}m, and 2.1 kA/cm{sup 2} at 1.21 {mu}m.

Hydrogen plasma processing of GaAs and AlGaAs using an electron cyclotron resonance plasma reactor, which is vacuum‐linked to a molecular‐beam epitaxial (MBE) growth chamber is reported. Native oxide removal and surface cleaning of GaAs is characterized using hydrogen plasma processing, subsequent thermal Cl2 etching, and vacuum annealing. It is shown that surface reconstruction and excellent GaAs/GaAs interfaces can be achieved using these dry vacuum procedures. It is also shown that AlxGa1−xAs native oxides can be removed for 0≤x≤1 using hydrogen plasma processing before MBE overgrowth. The best AlGaAs/AlGaAs interfaces are obtained using low microwave power during hydrogen plasma processing. O and C impurities detected at these interfaces increase with higher Al composition; Si interface impurities tend to increase with higher microwave power. In general, hydrogen plasma processing is judged effective for surface preparation before MBE growth for the complete range of AlGaAs alloys.

The novel fabrication of buried active region index‐guided GaAs/AlGaAs vertical‐cavity surface emitting lasers (VCSELs) using vacuum integrated fabrication is reported. Electron cyclotron resonance plasma etching and molecular beam epitaxial (MBE) regrowth are linked by an ultrahigh vacuum transfer tunnel to avoid air exposure of reactive AlGaAs surfaces. MBE regrowth on etched AlGaAs/AlAs heterostructures shows good quality epitaxial overgrowth exhibiting microtwin plates but few dislocation defects. Applying this regrowth technology to VCSEL fabrication, devices are obtained which exhibit laser emission over a wider current range and higher output power than etched air‐post VCSELs. The room‐temperature continuous wave characteristics demonstrate efficient current confinement and low thermal impedance for the etched/regrown lasers. Vacuum integrated fabrication promises further performance and functionality enhancements for VCSELs and other optoelectronic devices.

We demonstrate that electron cyclotron resonance plasma etching with a magnetically confined plasma in the region of the sample produces an enhanced etch rate, an anisotropic etch profile, and low self‐bias voltage. Results are presented for GaAs etch rates, etch profiles, and macroscopic etch uniformity using a SiCl4 plasma, comparing the effects of a confining magnetic field and a diverging magnetic field in the reactor. The etch rates and saturated ion current density to the sample are found to be correlated. An anisotropic near vertical etch profile with smooth‐etched surfaces is obtained with a negative self‐bias voltage of typically 5–25 V for electrically floating samples in a magnetically confined plasma. When the magnetic field lines are perpendicular to the sample surface, the measured macroscopic etch uniformity is ±6% across a 5 cm diam wafer.

We report the preparation of GaAs substrates, using only electron cyclotron resonance plasma techniques, and the subsequent growth of GaAs by molecular beam epitaxy, accomplished within an integrated processing facility. Exposure of the substrates to a hydrogen plasma with an ion current density less than 3 mA/cm2 for 1 h removes the native GaAs oxide leaving a smooth crystalline surface as revealed by streaky (1×1) reflection high energy electron diffraction patterns. At a greater ion current density a spotty diffraction pattern is obtained; a subsequent SiCl4 plasma etch restores a streaky (1×1) diffraction pattern. After plasma processing, evidence of surface reconstruction is observed at substrate temperatures greater than 400 °C in an As overpressure and during GaAs overgrowth. Impurity concentrations at the epilayer/substrate interfaces of plasma‐prepared samples are found to be comparable to those of chemically prepared wet etched substrates. This vacuum substrate preparation scheme is a first step...