Chemical Beam Epitaxy Technique Research Articles

Nitrogen-induced localized level observed by photoreflectance in GaAsN thin films grown by chemical beam epitaxy

Dilute nitride films of GaAsN with high nitrogen homogeneity were grown by using the chemical beam epitaxy technique. This allowed us to investigate the electronic structure of the nitrogen-induced localized level (EN) in GaAsN by photoreflectance measurements. We found that the EN value decreased as the nitrogen content increased. Consideration of the energy levels of isolated nitrogen (Nx); pairs of nitrogen atoms (NNi) where i=1, 2, and so on in order of increasing pair separation; and nitrogen clusters may help explain the changes in the estimated EN value.

Acceptor Levels due to a Complex Including the Nitrogen–Hydrogen Bond in GaAsN Films Grown by Chemical Beam Epitaxy

The acceptor levels and their concentration in GaAsN films grown by the chemical beam epitaxy technique were investigated through detailed analysis of the temperature dependence of hole concentration. Two acceptor levels A1 and A2 were found, and their energy levels were fixed at 130 ±20 and 55 ±10 meV, respectively, from the valence band maximum. Both concentrations were on the order of 1017 cm-3 and compensated by the concentration of donor on the same order. The concentration of A1 had a linear relationship with the number of N–H bonds in films grown at the same growth temperature, while the slope decreased with growth temperature. These results strongly suggested that a complex defect including the N–H bond was the origin of the A1 acceptor level.

Effective g-factor in high-mobility InGaAs/InP Quantum well

High-mobility In0.53Ga0.47As/InP quantum well is fabricated by the chemical beam epitaxy technique. Clear Shubnikov-de Hass (SdH) oscillation and beating pattern due to zero-field spin splitting are observed by magnetotransport measurements at low temperature. We use an analytical method, involving the simultaneous fitting of fast Fourier transform spectra of SdH oscillations at different tilted fields, to extract the effective g-factor.

Combinatorial Chemical Beam Epitaxy of Lithium Niobate Thin Films on Sapphire

A combinatorial chemical beam epitaxy technique was used to optimize deposition of {001} lithium niobate thin films on {001} sapphire substrates. Lithium tert-butoxide and niobium tetra-ethoxy di-methyl-amino-ethoxide were used as precursors. The highest quality films obtained exhibited rocking curve full-width at half-maximum values of about 0.03° and lithium contents larger than estimated by Raman spectroscopy. High-resolution transmission electron microscopy observations revealed that the lithium niobate film consists of a buffer layer (thickness ) with a high density of defects above which the epitaxial lithium niobate film was obtained.

Chemical beam epitaxial growth of GaInP using TBP, TIPGa and EDMIn

In this work the effects of growth temperature on the growth of gallium indium phosphide (GaInP) by the chemical beam epitaxy technique are reported. Triisopropylgallium, ethyldimethylindium and tertiarybutyl-phosphine were used as the gallium, indium and phosphorus sources, respectively. The growth rate, surface morphology, low temperature (15 K) and room temperature (300 K) photolumine-scence (PL) were studied as functions of the growth temperature. The optimum growth temperature was found to be 520°C where the PL spectra show only a single strong and narrow band edge peak.

New electrolytes for n-type InP and electrochemical C - V profiling of a semiconductor optical amplifier device structure

New electrolyte systems for profiling n-type indium phosphide (InP) have been reported and are compared with the conventional HCl electrolyte. Among the new electrolytes, the electrolyte comprising HNO3-HF-H2O has better characteristics and is best suited for profiling InP material. Both epitaxial layers and substrate materials have been subjected to electrochemical carrier concentration profiling using the new electrolyte and the estimated concentration values are compared with that of Hall effect measurements. Barrier heights of the new electrolytes have been calculated. For the first time, the dopant profiling of a complete device structure grown by the chemical beam epitaxy technique for the realization of laser and semiconductor optical amplifier structures has been presented.

Composition Change of Indium Oxide Film by Triethylgallium Irradiation Prepared for In Situ Selective Epitaxy Use

Selective epitaxy of GaAs was examined by the chemical beam epitaxy (CBE) technique on indium oxide masks. The indium oxide films were prepared in vacuum with an alternating supply of trimethylindium (TMIn) and H2O2. The irradiation of triethylgallium (TEGa) and AsH3 on the indium oxide films was performed to examine whether or not GaAs deposition takes place on the oxide films. After irradiation for 30 min above 450°C, drastic change in the chemical composition of the oxide films was observed. That is, indium atoms in the oxide films were replaced by gallium atoms. It was found that gallium atoms released on the oxide surfaces by TEGa decomposition promoted the sublimation of indium oxide through reduction. Two probable reactions are proposed for this sublimation process. The difference between indium oxide and gallium oxide in the suppression of TEGa decomposition is briefly discussed as well. The investigation shows that selective epitaxy of GaAs on the indium oxide masks can be achieved by the CBE technique using TEGa and AsH3, although the sublimation of the oxide limits the film thickness of epitaxial GaAs.

Chemical beam epitaxy

Abstract Chemical beam epitaxy (CBE), a new development in epitaxial technology, is being used more and more in research on compound semiconductors for device-oriented growth. CBE is a process in which metal alkyls (e.g., triethylgallium), as group 111 sources, and hydrides (e.g., mine). as group V sources, are used to form the corresponding intermetallic crystalline compound in an ultra-high vacuum (UHV) chamber. This article reviews the development of CBE technique for the growth of compound semiconductors, including problems which were solved to reach the current state of the art. The fundamental aspects of CBE growth are discussed, emphasizing fundamental advantages and disadvantages of CBE relative to other growth techniques such as MBE and MOVPE. Other aspects of CBE relating to purity, uniformity, surface morphology, and flexibility are also discussed. The current status of CBE materials and devices are summarized. Finally, some problemsthat remain to be solved are discussed and a few comments are made with respect to anticipated future developments.

Transport through InGaAs-InP superlattices grown by chemical beam epitaxy

We have studied the tunneling transport of several In0.53Ga0.47As-InP superlattices which were grown by the chemical beam epitaxy technique. When a high electric field is applied perpendicularly to the superlattice layers, the current-voltage characteristics show large negative differential resistances (NDRs) which are periodic in the applied field. The NDRs are caused by the regular expansion of a high-field domain within the superlattice. The regularity and large number of the NDRs observed demonstrate the high quality of the superlattices grown. They also point to their possible application in multiple-logic circuits. The temperature and magnetic-field dependence of the tunneling transport are also reported. In the high-field regime, the magnetic-field dependence is most remarkable for the large effect of the Lorentz force on the tunneling probability, while the temperature dependence of the different series of NDRs may be explained by the varying effectiveness of the phonon scattering on the width of different subbands.