High-resolution X-ray Rocking Curve Research Articles

Radiative emission mechanism analysis of green InGaN/GaN light-emitting diodes with the Si-doped graded short-period superlattice

The optical features of green InGaN/GaN light-emitting diodes (LEDs) with a graded Si-doped short-period InGaN/GaN superlattice (GSL) were examined by photoluminescence spectroscopy (PL). The power dependency of the PL peak energy and the linewidth (FWHM) at low temperatures showed that the Coulomb screening effects of Quantum confined stark effect and localized state filling are dominant processes for low and high excitation power, respectively. An increase in temperature activated the non-radiative centers at low excitation power. The abnormal temperature dependence of the peak energy indicated that the carrier dynamic is changed by the temperature owing to the spatial fluctuations of the In content and subsequent change in the state of carrier localization in InGaN/GaN MQWs. The localization effects were analyzed in the structure by fitting the temperature-dependent emission energy and utilizing a band-tailed model. The emission wavelength of the green InGaN/GaN LED with the GSL was 555 nm at 25 K and was red-shifted with increasing temperature up to 115 K. Then, it becomes blue-shift with further increases in the ambient temperature up to 260 K at low excitation power. The internal quantum efficiency was associated with the conversion from non-radiative to the radiative mechanism and is related to the carriers escaping from the localized state. The measured strain using the high-resolution x-ray rocking curve indicates that the strain of the structure is reduced because of the GSL layer. The strained structure shows a strong localization, and high efficiency. In addition, low power and high thermal energy are needed to enhance the localization effect and efficacy.

X-ray diffraction analysis and X-ray topography of high-quality ScAlMgO4 substrates

X-ray diffraction analysis through high-resolution X-ray rocking curve measurement and X-ray topography was performed on Czockralski (CZ) -grown ScAlMgO4 (SAM) substrates. An extremely narrow rocking curve width of 0.002° (7.2 arcsec) was obtained, and the three-dimensional (3D) configuration of dislocations in the interior of the SAM crystal structure was analyzed through 3D section topography. Burgers vectors of dominating dislocations with slip planes of (0001) were determined to be parallel to the a-axis of the SAM crystal, and the dislocations were found to form clusters.

GaAs-based optoelectronics grown on GaAs/Si virtual substrates with multiple spaced thermal-cycle annealing

This paper describes the growth of a GaAs-based light-emitting diode (LED) on a GaAs/Si virtual substrate by metalorganic chemical vapor deposition. A GaAs/Si virtual substrate (or template) was formed by depositing a 3.5-μm-thick GaAs epilayer on a (100) Si substrate with the employment of multiple spaced thermal-cycle annealing (TCA). The number of annealing cycle was zero to five in this study to examine crystallinity variation of a GaAs/Si template. High-resolution X-ray rocking curve analysis showed that (400) GaAs crystallinity in terms of full width at half maximum (FWHM) improved significantly with the number of the spaced TCA and then reached a minimum at four annealing cycles. There seems to be no significant difference in crystallinity between the GaAs/Si templates with four and five spaced annealing cycles. The GaAs/Si template with four spaced annealing cycles demonstrated not only an excellent (400) FWHM value of 94.6 arcsec but also a reduced dislocation density of 2.4 × 107 cm−2 evaluated from plan-view transmission electron microscopic observation. Electroluminescence spectra of GaAs-based LEDs grown on GaAs/Si templates showed that emission peak intensity increased monotonically with the number of the spaced annealing cycles. Furthermore, the emission peak intensity of a LED grown on the GaAs/Si template with five spaced annealing cycles reached 80% of a reference LED grown on a GaAs substrate, indicating that the presented multiple spaced TCA method may be useful in obtaining superior crystallinity of a GaAs/Si template for the potential application of monolithic integration of optoelectronic devices with Si.

Crystal growth and physico-chemical characterization of semi-organic [C4H12N2] ZnCl4·H2O single crystal for laser applications

Optical high-quality semi-organic piperazinium tetrachlorozincate monohydrate, [C4H12N2] ZnCl4·H2O (PTCZ), single crystals were grown by conventional solution method. The structure of grown crystal was confirmed by the single-crystal X-ray diffraction (SXRD) analysis. The material phase purities and its various (hkl) planes have been confirmed by the powder X-ray diffraction (PXRD) analysis at room temperature. The different functional groups were confirmed by the Fourier transform infrared (FTIR) spectroscopy. The optical quality of the PTCZ single crystal and band gap energy have been identified by the UV–Vis–NIR spectral analysis and also calculated refractive index of the material. The thermal stability of the PTCZ single crystal was investigated by TG–DTA. The hardness-related properties were analyzed by microhardness tester. The dielectric properties have been measured on the grown single crystal and the electronic polarizability value has been calculated with various theoretical approaches. The etching was carried out on the grown crystal to find the dislocation density. The crystal atomic perfection has been investigated by the high-resolution X-ray diffraction (HRXRD) or Rocking curve (RC) analysis. The Z-scan measurement has been carried out to find third-order optical susceptibility (χ(3)) of the grown single crystal using solid-state laser (640 nm).

Fast-response symmetric coplanar Ni/AlGaInP/Ni visible photodetector

A symmetric coplanar metal-semiconductor-metal structure has been successfully fabricated on a quaternary thin film of (AlxGa1-x)yIn1-yP epitaxially grown on (100) semi-insulating GaAs (SI-GaAs) substrate for visible photodetection. The crystallinity and alloy composition of the grown material was investigated with the help of high-resolution x-ray rocking curve and photoluminescence experiment giving the values of y = 0.66 and x = 0.67. The low-temperature photoluminescence study also gave insight into the defect levels in the material. The dark current-voltage curve was fitted by employing a back-to-back connected two-diode model to extract the barrier heights and ideality factor of the nickel contacts which were found to be 0.84 eV, 0.82 eV and 1.014, respectively. The photo-response of the device was studied in the wavelength range of 300−1000 nm which exhibited a peak at 610 nm. The maximum peak responsivity, detectivity and photosensitivity at a fixed applied bias of +15 V appeared to be 1.62 AW−1, 6.34 × 1011 cmHz1/2W-1 and 2.26 × 105 cm2W−1, respectively whereas under −15 V these values were 0.6 AW−1, 2.37 × 1011 cmHz1/2W−1, and 8.72 × 104 cmW−1, respectively in the presence of 610 nm illumination with optical power of 2 μW/cm2. The photodetector showed a rise time of 91 μs and the decay characteristics exhibited two channels of 83 μs and 282 μs, which are quite fast considering the temporal performance of similar kinds of devices. The photocurrent showed sub-linear power dependence with an increasing optical intensity which further refers to the recombination of photogenerated electron-hole pairs through trap and recombination centres within the forbidden gap.

High Homogeneity of Magnesium Doped LiNbO3 Crystals Grown by Bridgman Method

A series of LiNbO3 crystals doped with various MgO concentrations (0, 3%, and 5 mol%) was simultaneously grown in one furnace by the modified vertical Bridgman method. The wet chemistry method was used to prepare the polycrystalline powders, and the growth conditions were optimized. The full width at half maximum of high-resolution X-ray rocking curves for (001) reflection of 5 mol% Mg doped lithium niobate (LN) crystal was about 8″, which meant it possessed high crystalline quality. The OH− absorption spectra shifted to 3534.7 cm−1, and the UV absorption edge violet shift indicated that 5 mol% MgO successfully doped in LN and exceeded the threshold. The extraordinary refractive index gradient of 5 mol% Mg doped LN crystal was as small as 2.5 × 10−5/cm, which exhibited high optical homogeneity.

(Invited) X-Ray Metrology of AlN Single Crystal Substrates

As development of GaN and SiC material systems for applications in power switching progresses, the ultrawide-bandgap (UWBG) materials, with bandgaps greater than GaN, are gaining increased attention, in pursuit of improved power device performance. Substrate technology is critical to improve this field. High-quality native substrates, possessing low lattice and thermal expansion mismatches to epitaxial active layers, enable epitaxial growth with low densities of extended defects, leading to improved device performance and lifetime. Lateral and vertical power switching devices have been demonstrated in the emerging AlGaN alloy system [1]. Aluminum nitride (AlN) possesses a close lattice match to high Al mole fraction AlGaN alloys and a high thermal conductivity, which make it an excellent substrate for UWBG AlGaN-based devices. Physical vapor transport (PVT) growth has emerged as the most promising technique for the production of large, high-quality AlN single crystal substrates. Seeded growth technology developed by HexaTech enables iterative expansion of single crystal size, while suppressing low angle grain boundary (LAGB) formation, a primary source of grown-in dislocations. X-ray diffraction (XRD) is well suited to accurately and non-destructively probe the extended defect structure, composition, and strain of single crystals and epitaxial films. A variety of x-ray techniques were used throughout AlN substrate processing, from evaluation of as-grown crystals, through substrate polishing, to analysis of epitaxial films grown on AlN. High-resolution x-ray rocking curves (HRXRRC) and x-ray topography (XRT) were used to determine the primary dislocation types in AlN bulk crystals and their likely formation mechanisms [2, 3]. Synchrotron-based XRT images demonstrated that the expanded diameter of freestanding AlN boules contained low densities of threading dislocations (<104 cm-3), and no basal plane dislocations or LAGBs [4]. Furthermore, XRT images acquired on a commercial diffractometer were used for quality control of AlN seed crystals. The advent of a new generation of x-ray area detectors, capable of a wide dynamic range and rapid data acquisition, opened the possibility for using XRT in production. HRXRRC and surface-sensitive reciprocal space maps were used to monitor sub-surface damage removal during substrate polishing [5]. These results, together with atomic force microscopy and defect selective etching images, demonstrated that chemo-mechanically polished AlN surfaces were free of plastic damage [4]. Polished AlN surfaces were also studied by x-ray reflectivity, yielding long-range data about surface roughness and density. Finally, epitaxial AlGaN films and heterostructures deposited on AlN substrates were studied by a combination of these x-ray techniques, providing essential information on composition, thickness, relaxation, and heterostructure design. XRD has become a valuable metrology tool in the development of AlN technology. This talk will review the implementation of complementary x-ray based measurements in the processing of AlN, from boule growth to AlGaN-based devices.

Laser molecular beam epitaxy growth of porous GaN nanocolumn and nanowall network on sapphire (0001) for high responsivity ultraviolet photodetectors

We report on high-responsivity metal-semiconductor-metal (MSM) structure based ultraviolet (UV) GaN photodetectors fabricated on various GaN nanostructures such as porous nanocolumn network (PNCN), nanowall networks (NWNs), and granular and compact thin films. Different GaN nanostructures were hetero-epitaxially grown on c-sapphire using laser molecular beam epitaxy by tuning the AlN buffer layer growth parameters. High resolution x-ray rocking curve measurements indicate that the crystalline quality of GaN critically depends on the selection of AlN buffer layer growth conditions such as type of ablation target and growth temperature. The porous GaN nanostructures revealed a nearly stress-free wurtzite structure as deduced by Raman spectroscopy measurements. Room temperature photoluminescence spectroscopy showed that the GaN films possess a near band emission (NBE) peak at ∼ 3.39 eV along with a broad yellow luminescence (YL) with maxima at 2.25 eV. For GaN PNCN and NWN structures, the NBE-to-YL emission ratio is more than an order higher compared to the GaN films. The fabricated MSM based UV-detector on GaN PNCN and NWN exhibited a high photo-responsivity of ∼27.72 and 24.8 A/W, respectively, under 2 V applied bias at room temperature. The GaN PNCN and NWN nanostructures with excellent photo-responsivity and optical quality prove to be promising candidates for the fabrication of efficient UV photodetectors due to their continuity in lateral direction, high surface area-to-volume ratio and tailored surfaces.

Regrowth of GaN on Strain-relief porous GaN template fabricated by Anodized Alumina Oxide mask

The growth of Gallium nitride on sapphire substrate generated a high density of threading dislocations in the order of ~108-109 /cm2. In this work, porous GaN template with different pore sizes was generated using Anodized Alumina oxide mask prepared by anodization with set voltage ranging from 40 V to 100V. Inductive coupled plasma etching generated porous GaN using the oxide mask. The etched pores have an estimated depth of 150 nm and the pores diameter range from 35 nm to 150 nm. Regrowth of GaN with embedded air voids provide a strain relaxed overgrown GaN layer with dislocation annihilation at the voids region. High resolution X-ray rocking curves at the symmetrical plane (002), (004) and (006) was obtained for the overgrown GaN demonstrate a significant reduction in FWHM for overgrown GaN on porous GaN template as compared to conventional GaN template. Dislocation density reduction estimated using Ayer model revealed an order of magnitude reduction of screw and mixed dislocation to higher order of 107cm-2 for overgrown on porous GaN with size of 70 nm to 100nm. Pits density counts which can be correlated to threading dislocations in the materials shows that the regrowth GaN samples on strain relief GaN has an order of magnitude lower pits density as compared to that conventional GaN sample.

Perovskite CH3NH3PbI3(Cl) Single Crystals: Rapid Solution Growth, Unparalleled Crystalline Quality, and Low Trap Density toward 10(8) cm(-3).

Single crystal reflects the intrinsic physical properties of a material, and single crystals with high-crystalline quality are highly desired for the acquisition of high-performance devices. We found that large single crystals of perovskite CH3NH3PbI3(Cl) could be grown rapidly from chlorine-containing solutions. Within 5 days, CH3NH3PbI3(Cl) single crystal as large as 20 mm × 18 mm × 6 mm was harvested. As a most important index to evaluate the crystalline quality, the full width at half-maximum (fwhm) in the high-resolution X-ray rocking curve (HR-XRC) of as-grown CH3NH3PbI3(Cl) single crystal was measured as 20 arcsec, which is far superior to so far reported CH3NH3PbI3 single crystals (∼1338 arcsec). The unparalleled crystalline quality delivered a low trap-state density of down to 7.6 × 10(8) cm(-3), high carrier mobility of 167 ± 35 cm(2) V(-1) s(-1), and long transient photovoltaic carrier lifetime of 449 ± 76 μs. The improvement in the crystalline quality, together with the rapid growth rate and excellent carrier transport property, provides state-of-the-art single crystalline hybrid perovskite materials for high-performance optoelectronic devices.

Influence of laser repetition rate on the structural and optical properties of GaN layers grown on sapphire (0001) by laser molecular beam epitaxy

High-quality GaN layers were grown on sapphire (0001) substrates using laser molecular beam epitaxy (LMBE) by laser ablating a solid GaN target at different laser repetition rates (10–40 Hz) under a constant supply of r.f. nitrogen plasma. The effect of laser repetition rate on the structural and optical properties of GaN layers was systematically studied using high-resolution X-ray diffraction (HRXRD), field emission scanning electron microscopy, atomic force microscopy, Raman spectroscopy and photoluminescence (PL) spectroscopy. High-resolution X-ray rocking curve measurements revealed highly c-axis oriented GaN layers on sapphire grown at 30 Hz with a calculated screw dislocation density of ~1.42 × 107 cm−2, whereas the GaN layers grown at 10 or 40 Hz consisted the screw dislocation density in the range of 108–109 cm−2. Surface morphological analysis revealed a change in grain size as well as surface roughness as a function of laser repetition rate and is explained on the basis of growth kinetics. Vibrational Raman spectroscopy revealed that the GaN layer grown at 10 Hz shows an in-plane compressive stress of ~1 GPa, while the film grown at 30 Hz exhibits a minimum stress of ~0.3 GPa. The PL measurements show a highly luminescent band-to-band emission of GaN at 3.44 eV for the 10 Hz grown highly strained GaN layer and at 3.41 eV for the less strained film grown at 30 Hz along with a broad defect band emission centered around 2.28 eV. It is found that the GaN layers grown at 30 Hz have excellent structural and optical properties. We expect that the less strained thin and highly oriented GaN film grown by LMBE can further be utilized for developing prodigious low-temperature-grown nitride-based multilayer structures and devices.

High Resolution X-ray Diffraction Studies of MBE-Grown HgCdTe Layers on Bulk-Grown CdZnTe Substrate

The structural properties of molecular beam epitaxially (MBE)-grown Hg1−x Cd x Te epilayers on CdZnTe (211) substrate have been investigated using high-resolution x-ray topography and rocking curves. High-resolution x-ray diffraction 2θ–θ scans of (422) reflections were utilized in calculating the out-of-plane lattice parameters of the HgCdTe layer and the CdZnTe substrate. The lattice strain of the HgCdTe layer was evaluated using the in-plane measurements of the (311) reflection. Etching seemed to improve the surface of the substrate by removing any damage caused by polishing or any post-processing. In spite of some localized line dislocations, a remarkable quality of the MBE-grown HgCdTe layer was observed. The full width at half maximum values of the HgCdTe layer and the CdZnTe substrate were determined as 43 arc-s and 16.2 arc-s, respectively.

Accurate determination of surface orientation of single-crystal wafers using high-resolution X-ray rocking curve measurements

Theoretical models of the variations of the peak positions of X-ray rocking curves as a function of the azimuthal angle of a single-crystal wafer have been proposed. These models completely describe the variations of the peak positions both when the surface normal of a wafer is parallel and when it is not parallel to the rotation axis of the goniometer used. Based on the models, an accurate measurement method for the surface orientation of a single-crystal wafer with a small surface miscut of &lt;∼3° has been proposed through rocking curve measurements using a high-resolution X-ray diffractometer. The method measures the misalignment of the sample surface normal with respect to the rotation axis of the goniometer as well as the surface orientation of the wafer. The surface orientation has been measured for a 6 inch (152.4 mm) single-crystal sapphire wafer, and the misalignment of the surface normal from the rotation axis was determined. The results were compared with those from a different method. In addition, a simple and accurate method to obtain the surface orientation of a wafer is proposed by measuring only four rocking curves, two each at two sample azimuths 180° apart.

Structural and optical investigation of non-polar (1-100) GaN grown by the ammonothermal method

We studied the structural and optical properties of state-of-the-art non-polar bulk GaN grown by the ammonothermal method. The investigated samples have an extremely low dislocation density (DD) of less than 5 × 104 cm−2, which results in very narrow high-resolution x-ray rocking curves. The a and c lattice parameters of these stress-free GaN samples were precisely determined by using an x-ray diffraction technique based on the modified Bond method. The obtained values are compared to the lattice parameters of free-standing GaN from different methods and sources. The observed differences are discussed in terms of free-electron concentrations, point defects, and DD. Micro Raman spectroscopy revealed a very narrow phonon linewidth and negligible built-in strain in accordance with the high-resolution x-ray diffraction data. The optical transitions were investigated by cathodoluminescence measurements. The analysis of the experimental data clearly demonstrates the excellent crystalline perfection of ammonothermal GaN material and its potential for fabrication of non-polar substrates for homoepitaxial growth of GaN based device structures.

Ultra-high frequency photoconductivity decay in GaAs/Ge/GaAs double heterostructure grown by molecular beam epitaxy

GaAs/Ge/GaAs double heterostructures (DHs) were grown in-situ using two separate molecular beam epitaxy chambers. High-resolution x-ray rocking curve demonstrates a high-quality GaAs/Ge/GaAs heterostructure by observing Pendellösung oscillations. The kinetics of the carrier recombination in Ge/GaAs DHs were investigated using photoconductivity decay measurements by the incidence excitation from the front and back side of 15 nm GaAs/100 nm Ge/0.5 μm GaAs/(100)GaAs substrate structure. High-minority carrier lifetimes of 1.06-1.17 μs were measured when excited from the front or from the back of the Ge epitaxial layer, suggests equivalent interface quality of GaAs/Ge and Ge/GaAs. Wavelength-dependent minority carrier recombination properties are explained by the wavelength-dependent absorption coefficient of Ge.

Structural, morphological, and band alignment properties of GaAs/Ge/GaAs heterostructures on (100), (110), and (111)A GaAs substrates

Structural, morphological, and band offset properties of GaAs/Ge/GaAs heterostructures grown in situ on (100), (110), and (111)A GaAs substrates using two separate molecular beam epitaxy chambers, connected via vacuum transfer chamber, were investigated. Reflection high energy electron diffraction (RHEED) studies in all cases exhibited a streaky reconstructed surface pattern for Ge. Sharp RHEED patterns from the surface of GaAs on epitaxial Ge/(111)A GaAs and Ge/(110)GaAs demonstrated a superior interface quality than on Ge/(100)GaAs. Atomic force microscopy reveals smooth and uniform morphology with surface roughness of Ge about 0.2–0.3 nm. High-resolution triple axis x-ray rocking curves demonstrate a high-quality Ge epitaxial layer as well as GaAs/Ge/GaAs heterostructures by observing Pendellösung oscillations. Valence band offset, ΔEv, have been derived from x-ray photoelectron spectroscopy (XPS) data on GaAs/Ge/GaAs interfaces for three crystallographic orientations. The ΔEv values for epitaxial GaAs layers grown on Ge and Ge layers grown on (100), (110), and (111)A GaAs substrates are 0.23, 0.26, 0.31 eV (upper GaAs/Ge interface) and 0.42, 0.57, 0.61 eV (bottom Ge/GaAs interface), respectively. Using XPS data obtained from these heterostructures, variations in band discontinuities related to the crystallographic orientation have been observed and established a band offset relation of ΔEV(111)Ga&amp;gt;ΔEV(110)&amp;gt;ΔEV(100)As in both upper and lower interfaces.

In situ grown Ge in an arsenic-free environment for GaAs/Ge/GaAs heterostructures on off-oriented (100) GaAs substrates using molecular beam epitaxy

High-quality epitaxial Ge layers for GaAs/Ge/GaAs heterostructures were grown in situ in an arsenic-free environment on (100) off-oriented GaAs substrates using two separate molecular beam epitaxy (MBE) chambers, connected via vacuum transfer chamber. The structural, morphological, and band offset properties of these heterostructures are investigated. Reflection high energy electron diffraction studies exhibited (2 × 2) Ge surface reconstruction after the growth at 450 °C and also revealed a smooth surface for the growth of GaAs on Ge. High-resolution triple crystal x-ray rocking curve demonstrated high-quality Ge epilayer as well as GaAs/Ge/(001)GaAs heterostructures by observing Pendellösung oscillations and that the Ge epilayer is pseudomorphic. Atomic force microscopy reveals smooth and uniform morphology with surface roughness of ∼0.45 nm and room temperature photoluminescence spectroscopy exhibited direct bandgap emission at 1583 nm. Dynamic secondary ion mass spectrometry depth profiles of Ga, As, and Ge display a low value of Ga, As, and Ge intermixing at the Ge/GaAs interface and a transition between Ge/GaAs of less than 15 nm. The valence band offset at the upper GaAs/Ge-(2 × 2) and bottom Ge/(001)GaAs-(2 × 4) heterointerface of GaAs/Ge/GaAs double heterostructure is about 0.20 eV and 0.40 eV, respectively. Thus, the high-quality heterointerface and band offset for carrier confinement in MBE grown GaAs/Ge/GaAs heterostructures offer a promising candidate for Ge-based p-channel high-hole mobility quantum well field effect transistors.

Analyses of hetero-interface trapping properties in AlGaN/GaN high electron mobility transistor heterostructures grown on silicon with thick buffer layers

We report on the analyses of trapping properties of metal-organic chemical vapor deposition grown AlGaN/GaN high-electron-mobility transistor (HEMT) heterostructures on silicon with increasing buffer thickness (Tbuff). An exact exponential dependence of AlGaN/GaN hetero-interface trap time constants with gate bias was observed in the vicinity of threshold voltage. A low hetero-interface state density (Dit) value of ∼2.5 × 1010 cm−2 eV−1 was achieved for heterostructures grown by using thick Tbuff ∼ 5 μm against a Dit value of ∼1 × 1011 cm−2 eV−1 for a similar heterostructures grown with thin Tbuff ∼ 1.25 μm. Further, the high resolution x-ray rocking curve and Van der Pauw-Hall measurements also confirmed that increasing the Tbuff improves the AlGaN/GaN HEMT heterostructures with reduced edge dislocation densities and enhanced carrier transport properties.

High-Dose Phosphorus-Implanted 4H-SiC: Microwave and Conventional Post-Implantation Annealing at Temperatures ≥1700°C

Semi-insulating 4H-SiC ⟨0001⟩ wafers have been phosphorus ion implanted at 500°C to obtain phosphorus box depth profiles with dopant concentration from 5 × 1019 cm−3 to 8 × 1020 cm−3. These samples have been annealed by microwave and conventional inductively heated systems in the temperature range 1700°C to 2050°C. Resistivity, Hall electron density, and Hall mobility of the phosphorus-implanted and annealed 4H-SiC layers have been measured in the temperature range from room temperature to 450°C. The high-resolution x-ray diffraction and rocking curve of both virgin and processed 4H-SiC samples have been analyzed to obtain the sample crystal quality up to about 3 μm depth from the wafer surface. For both increasing implanted phosphorus concentration and increasing post-implantation annealing temperature the implanted material resistivity decreases to an asymptotic value of about 1.5 × 10−3 Ω cm. Increasing the implanted phosphorus concentration and post-implantation annealing temperature beyond 4 × 1020 cm−3 and 2000°C, respectively, does not bring any apparent benefit with respect to the minimum obtainable resistivity. Sheet resistance and sheet electron density increase with increasing measurement temperature. Electron density saturates at 1.5 × 1020 cm−3 for implanted phosphorus plateau values ≥4 × 1020 cm−3, irrespective of the post-implantation annealing method. Implantation produces an increase of the lattice parameter in the bulk 4H-SiC underneath the phosphorus-implanted layer. Microwave and conventional annealing produce a further increase of the lattice parameter in such a depth region and an equivalent recovered lattice in the phosphorus-implanted layers.

Characterization and analysis of epitaxial silicon phosphorus alloys for use in n-channel transistors

In this work, we demonstrate substitutional phosphorus concentration as high as 12at.% in epitaxial silicon. It is observed that 10at.% substitutional phosphorus doping is equivalent in tensile strain to incorporating 2.1at.% substitutional carbon into the silicon lattice. Phosphorus doping of this order produces tensile strain levels suitable for n-channel metal-oxide semiconductor field-effect transistor uniaxial stressor applications. This work focuses on the experimental and theoretical analyses of phosphorus doped silicon based on high resolution X-ray rocking curves, secondary ion mass spectroscopy, Rutherford backscattering spectroscopy, and molecular dynamic modeling.