Fabrication of monolithic lattice-mismatched semiconductor heterostructures with limited area regions having upper portions substantially exhausted of threading dislocations, as well as fabrication of semiconductor devices based on such lattice-mismatched heterostructures.

Lattice-Mismatched Semiconductor Structures with Reduced Dislocation Defect Densities and Related Methods for Device Fabrication

Methods of forming structures that include InP-based materials, such as a transistor operating as an inversion-type, enhancement-mode device. A dielectric layer may be deposited by ALD over a semiconductor layer including In and P. A channel layer may be formed above a buffer layer having a lattice constant similar to a lattice constant of InP, the buffer layer being formed over a substrate having a lattice constant different from a lattice constant of InP.

InP-Based Transistor Fabrication

Semiconductor structures include a trench formed proximate a substrate including a first semiconductor material. A crystalline material including a second semiconductor material lattice mismatched to the first semiconductor material is formed in the trench. Process embodiments include removing a portion of the dielectric layer to expose a side portion of the crystalline material and defining a gate thereover. Defects are reduced by using an aspect ratio trapping approach.

Tri-gate field-effect transistors formed by aspect ratio trapping

Progress in metal-organic chemical vapor deposition of high quality N-polar (Al, Ga, In)N films on sapphire, silicon carbide and silicon substrates is reviewed with focus on key process components such as utilization of vicinal substrates, conditions ensuring a high surface mobility of species participating in the growth process, and low impurity incorporation. The high quality of the fabricated films enabled the demonstration of N-polar (Al, Ga, In)N based devices with excellent performance for transistor applications. Challenges related to the growth of high quality N-polar InGaN films are also presented.

Recent progress in metal-organic chemical vapor deposition of $\left( 000\bar{1} \right)$ N-polar group-III nitrides

This article comprehensively reviews the growth of III–V antimony-based semiconductor materials using metal-organic chemical vapor deposition (MOCVD). It does this by first discussing the general trends found for the growth of these materials. Next the specific growth techniques are discussed for each of the antimony-based systems including the binaries InSb, GaSb, and AlSb. The growth techniques used for many of the ternaries and quaternaries of these materials are also discussed. Following this a brief description of the use of dopants, novel organometallic sources and superlattices is presented. Next, the use of common characterization techniques is presented for different types of materials. A variety of the types of devices is then presented followed by a short summary and forecast of future directions that are currently being pursued in these materials.

The metal-organic chemical vapor deposition and properties of III–V antimony-based semiconductor materials

Low-pressure MOCVD has been used to grow layers of InP, InGaAs, GaInAsP and quantum well material on planar substrates patterned with silica masks. The thicknesses and, where relevant, the compositions of these selectively grown layers were investigated by optical and scanning electron microscopy, surface profiling, energy dispersive X-ray analysis, secondary-ion mass spectroscopy and spatially resolved photoluminescence. The epitaxial layers were found to be both thicker and richer in indium in the vicinity of a mask. The perturbations in the thickness and composition of material grown around a given mask pattern were independent of the orientation of the pattern with respect to the gas flow and the crystallographic axes of the substrate. Lateral movement of material from the masked regions to the surrounding areas was found to take place in the gas above the water surface. A gas-phase diffusion model based on Laplace's equation was used to analyze the thickness and compositional variations caused by selective growth. The emission wavelength of selectively grown InGaAs/GaInAsP MQW material was shifted by over 100 nm without degradation in emission efficiency. The lasing wavelength of Fabry-Perot lasers fabricated on such material was increased by a similar amount without degradation of threshold current.

https://iopscience.iop.org/article/10.1088/0268-1242/8/6/006/pdf

Selective-area low-pressure MOCVD of GaInAsP and related materials on planar InP substrates

GaSb heterostructures grown by MOVPE

Single and multiple quantum wells of GaSb/GaInSb were grown by metalorganic vapor phase epitaxy. X‐ray diffraction on an 80 A single well confirmed the Ga1−xInxSb composition to be x=0.15, for which the lattice mismatch is ≊1.0%. Photoluminescence and photoconductivity from this sample both showed a signal due to carriers in the well, the position of which was in good agreement with the calculated band diagram. Shubnikov–de Haas oscillations in the transverse magnetoresistance (ρxx) of a four‐period multiquantum well, and the associated quantum Hall effect, indicated that a two‐dimensional hole gas was present in one of the wells. Unusually, the strongest oscillations were seen for occupancy of an odd number of (spin split) Landau levels (ν=1,3,5,...,etc.) This sample also showed luminescence peaks at 738 and 755 meV which were attributed to recombination in the wells.

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GaSb/GaInSb quantum wells grown by metalorganic vapor phase epitaxy

The growth of strained GaSb/GaAs quantum wells has been attempted for the first time (7% lattice mismatch), with the antimonide layers being constrained to take on the GaAs lattice parameter in the interface plane. The critical thickness for pseudomorphic growth of the strained layer was about 15 A, with further growth resulting in islands of GaSb crystallites over the wafer surface. Photoluminescence spectra and photoconductivity from both single and double wells showed a strong signal at approximately 1.3 eV, identified as a Γ point transition. This was not consistent with band structure calculations for a GaSb/GaAs well, suggesting an error in the estimation of the band offsets and/or As incorporation in the strained layer.

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GaAs/GaSb strained‐layer heterostructures deposited by metalorganic vapor phase epitaxy

The authors report on the structural and optical characterization of nominally lattice-matched GaInAs/GaInAsP multiple quantum well (MQW) structures grown on (100) InP substrates by metalorganic chemical vapour deposition (MOCVD) which undergo a 'blue shift' in photoluminescence upon thermal annealing. Electron microscope and magneto-optical analyses show that the shifts are principally due to layer interdiffusion, which results in a change in composition of the well centres. These compositional variations are quantitatively measured by high-resolution analytical electron microscopy. This analysis demonstrates that the diffusion of the group V elements in the undoped MQWS is faster than that of the group III elements, resulting in the incorporation of excess coherency strain in the material. Analysis of a number of samples grown on a variety of substrates shows that the wavelength shift is particularly large when the substrates are S doped, although the substrate dopant does not participate directly in the diffusion mechanism. The authors attribute this behavior to the typically low dislocation density of S-doped substrates. They report, for the first time, a direct measurement of the correlation between the spatial variation in the magnitude of the blue shift and the presence of dislocations in the MQWS.

R. E. Mallard

Papers

Selective-area low-pressure MOCVD of GaInAsP and related materials on planar InP substrates

GaSb heterostructures grown by MOVPE

GaSb/GaInSb quantum wells grown by metalorganic vapor phase epitaxy

GaAs/GaSb strained‐layer heterostructures deposited by metalorganic vapor phase epitaxy

The control and evaluation of blue shift in GaInAs/GaInAsP multiple quantum well structures for integrated lasers and Stark-effect modulators