InSb Single Crystals Research Articles

Epitaxial growth of InSb on sapphire by rf sputtering

InSb films have been deposited directly by rf sputtering on sapphire substrates. X-ray diffraction and scanning electron microscopy data are presented to show that the InSb layer on sapphire (0001) is epitaxial and grows with (111) parallel to the substrate surface. Optical absorption studies of the epitaxial film also reveal distinct spectral features which resemble these from bulk, single-crystal InSb.

Transmutation doping and lattice defects in degenerate InSb

n-type InSb single crystals were irradiated with thermal neutrons below T = 6 K. The Shubnikov-de Haas effect and the resistivity Q(T = 4.6 K) were measured as a function of the neutron dose and the holding temperature of a subsequent annealing program. The results are discussed in terms of the transport scattering rate and the lifetime of the Landau-levels. They have to be interpreted by means of n-doping due to nuclear reactions and irradiation induced negatively charged defects. Almost complete annealing of the transport parameters can be achieved by heating the samples to TA = 400 K.

Laser annealing of radiation damage in Be-implanted InSb single crystals

Ion backscattering and channeling of proton and helium beams have been used to study the effect of pulsed laser annealing of the radiation damage in ion-implanted InSb single crystals. The single crystals were implanted at room temperature with Be ions with a dose of 1 × 1016 ions/cm2 at energies of 100 and 200 keV. Although the laser annealing resulted in a significant decrease in the lattice disorder of the near-surface damaged region, a higher dechanneling rate at greater depths indicated that the structure could not be fully restored. However, in comparison with isochronal thermal annealing the application of pulsed laser beams rendered roughly the same single-crystal properties at energy densities above the melting point.

Analysis of impurity concentration distributions in pulled semiconductor crystals

InSb and GaSb single crystals were grown by the Czochralski method. The impurity concentration distribution in the melt and crystal was investigated experimentally and computationally as a function of the interface segregation coefficient, the shape of the solid-liquid interface and the growth rate. It was found that the impurity concentration distribution in the melt was largely influenced by the interface segregation coefficient; the impurity concentration in the crystal increased as the shape of the solid-liquid interface became more planar and also as the growth rate increased; the impurity concentration was more markedly influenced by the growth rate than by the shape of the solid-liquid interface. When the growth rate was large, the impurity concentration increased and the shape of the solid-liquid interface was concave toward the melt near the crystal periphery. When the growth rate was small, the impurity concentration decreased and the shape of the solid-liquid interface was convex toward the melt.

浮遊帯域溶融法によるInSb単結晶の成長

This paper shows the potential applications of the floating zone method to the growth of single crystals of InSb whose melts have high specific gravity and low surface tension.The maximum diameter of the single crystals that can be obtained by the method about 5 mm, because the molten zones with sizes up to 5 mm in diameter can only be sustained against the gravitational froce. The most suitable conditions for growth of the InSb single crystals were described. This paper also presents a new method to measure the surface tension from the equilibrium shape of the molten zones. By the method the surface tension of the molten InSb is determined to be 0.290 N/m.The single crystals obtained are characterized by X-ray topography, whose imperfections are mainly twining, stacking faults and dislocation loops.

Raman and Secondary Ion Mass Spectroscopy of Epitaxial CdTe/InSb Interfaces Grown by Low-Energy Bias Sputtering

ABSTRACTHeteroepitaxial (100)CdTe || (100)InSb structures have been fabricated by growing CdTe epilayers, at growth temperatures below 200°C, on single crystal InSb substrates by low-energy bias sputtering. Controlled low-energy ion bombardment at the substrate was employed to clean the growth surface in-situ just prior to film deposition and to modify the growth kinetics and enhance adatom mobility during deposition. Raman spectroscopy of the interface revealed no evidence of In2Te3 and secondary ion mass spectroscopy showed the interface to be chemically abrupt.

Neutron optical experiments at the IBR-2 pulsed reactor

At JINR, Dubna, a new DIFRAN facility has been installed on a neutron guide at the IBR-2 pulsed reactor. Results of preliminary experiments including investigations of neutron diffraction on bent perfect crystals, wavelength-dependent Pendellösung oscillations, anomalous transmission in InSb single crystals and the first successful test of a new three-plate monolithic interferometer are reported.

Exclusion of rotational striations in pulled crystals by an improved Czochralski method

An improved Czochralski method with the alternate rotation of a seed crystal was developed in order to homogenise impurities doped in InSb single crystals. When the crystal was pulled under one-directional rotation, the fluctuation width of the growth rate increased as the crystal periphery was approached from the centre, and rotational striations were formed. Under alternative rotation of the angle range of 18 degrees and 90 degrees , the fluctuation width of the growth rate was decreased to 15 and 70% in comparison with that of the one-directional rotation, respectively. The fluctuation of the growth rate then became small as the angle of alternate rotation became narrow. Thus, in a crystal pulled under 18 degrees alternate rotation, rotational striations were excluded and moreover the fluctuation of spreading resistance was also decreased from 22 to 15 Omega .

Low-temperature growth of InSb by vacuum MOCVD using TEln and SbH3

This report describes the homo-epitaxial growth of InSb by the Metal-Organic Chemical Vapor Deposition Method (MOCVD) using triethylindium (TEIn) and stibine (SbH3) for indium and antimony sources, respectively. Single crystal InSb layers were grown at 400° C. The gas flow rate ratio (= SbH3/TEIn) should be more than 8 in order to grow a layer with good morphology. The epitaxial layer was n-type, with a carrier density and mobility of 1.5 x 1016 cm-3 and 7.6 x 104 cm2/Vs, respectively, at 77 K. By inserting a buffer layer grown at 400° C, the single crystal InSb layer was grown even at 300° C.

X-ray topographic investigation of microdeformation of InSb single crystals

Abstract The dislocation distribution around indentations on ±(001) surfaces of highly perfect InSb single crystals has been studied by X-ray topography. Three types of dislocation loop have been identified. Type-I loops lie in {111} planes and are screw-B(g) or screw–A(g) type with ± ½[110] and ± ½[110] Burgers vectors. They can extend over I mm from the indentation site and penetrate up to 170 μm deep into the crystal. Type-11 dislocations, having the same Burgers vectors as type-I dislocations, are 100–150 μm long, 60°B(g) and A(g) dislocation half-loops reaching a depth of 70 μm and less than 30 μm respectively. These prismatic loops are believed to be introduced ab initio during indentation as well as to result from interaction of the first type of dislocation. Type-III dislocations are loops on {111} planes having their Burgers vectors parallel to these planes in 〈110〉 directions. They penetrate over 230 μm into the crystal and arise from the intersection of inclined type-I loops. The dislocation ro...

An Improved Czochralski Technique for Growing Single Crystals with High Homogeneity

InSb single crystals with high homogeneity were grown by an improved Czochralski technique. The distinctive feature of this technique is that a seed crystal is rotated alternately clockwise and counterclockwise within a narrow range of angles. The periodic fluctuation of the growth rate in InSb pulled crystals was remarkably decreased and, as a result, the impurity inhomogeneity was reduced.

The study of neutron acoustic effect by neutron diffraction on InSb single crystal

Experimental results are given of a neutron diffraction study of the anomalous transmission effect in InSb perfect single crystal influenced by high frequency ultrasonic vibrations. Evidence is shown for the suppression of this effect by means of the neutron acoustic resonant interaction. Quite a different nonresonant behaviour of the suppression is observed in the frequency region, corresponding to the own transducer vibration. Es werden experimentelle Ergebnisse einer Neutronenbeugungsuntersuchung zum Effekt der durch Ultraschallschwingungen bewirkten anomalen Neutronentransmission in idealen InSb-Einkristallen angegeben. Die Reduzierung des Effekts durch resonanzartige neutronenakustische Wechselwirkung wird nachgewiesen. Zusatzlich wird ein anderes resonanzloses Verhalten der Reduzierung in der Umgebung der Eigenfrequenz des Wandlers beobachtet.

Effect of In and Sb Vacancies on Temperature Dependence of InSb Lattice Parameter at High Temperatures

AbstractThe temperature dependence of the thermal expansion coefficient for InSb has been determined in the range 25–515 °C by precision measurements of the lattice parameter of InSb single crystals. It is shown that beginning from 460 °C the temperature dependence of the lattice parameter for InSb single crystals grown from melts of different compositions is essentially affected by vacancies in the indium and antimony sublattices. The vacancy concentration and possible deviation of InSb from the stoichiometric composition are estimated from a relative decrease in the lattice parameter.

Deposition of indium on Sb(111) single crystal: A low energy electron diffraction, Auger, and x-ray photoelectron spectroscopy interface investigation

Stepwise evaporations of indium have been done at room temperature on Sb(111) single crystals in order to study the interface and the InSb formation conditions. From the Auger measurements, we suggest a Stranski–Krastanov growth mode where the first monolayer seems to contain a significant amount of InSb. The InSb formation was further studied by Auger electron spectroscopy (AES) and x-ray photoelectron spectroscopy (XPS) by annealing a thick indium overlayer on Sb(111). Comparison is made to our measurements on an InSb single crystal and also to results from the literature. Low energy electron diffraction (LEED) shows the first monolayer to be disordered. However, the Sb single crystal covered with an indium overlayer restores a (2×2) or (1×1) LEED pattern after annealing, and InSb is formed in this case.

High voltage electron irradiation (1 MV, 2 MV) of prestrained InSb single crystals

High voltage electron irradiation (1 MV, 2 MV) of prestrained InSb single crystals

Detection of optical emission from InSb induced by pulsed laser evaporation

The results of in situ measurements of the optical emissions which occur during the deposition of InSb films by pulsed laser evaporation are reported. Evaporation was induced by a Q-switched neodymium : yttrium aluminum garnet laser with 90 ns pulse width and powers less than 1.5 mJ per pulse at a wavelength of 1.06 μm impinging on the surface of a rotating single crystal InSb target. At low laser powers, emission lines characteristic of In and Sb species were detected which decayed in 800 ns. At higher laser powers, emissions from excited atoms and/or ions were observed. Surface contamination of the target reduced the power threshold to produce ions.

S/N study of micro-hall sensors made of single crystal InSb and GaAs

Signal-to-noise (S/N) characteristics of various single crystal semiconductor micro-Hall sensors with an effectively magnetosensitive area less than 5 microns square are presented. Normal product sensitivity is typically 140 V/AT for an InSb sensor and 500 V/AT for a GaAs sensor. The magnetic sensitivity of a highly resistive GaAs micro-Hall sensor increases remarkably at a high electric field together with increasing current noise due to Gunn instability. A maximum magnetic sensitivity of 2.5 V/T was obtained. However, the S/N ratio of a GaAs sensor was much smaller than that of an InSb sensor with a high electron mobility. A high S/N ratio of 145 dB was obtained for an InSb micro-Hall sensor operated by an audio frequency of 1 kHz in a magnetic field of 0.1 T.

Interface reactions of copper films with polycrystalline indium or antimony and single- crystal InSb substrates

The results of investigations of interface reactions of copper films with polycrystalline indium or antimony and with InSb single crystals are presented. The interface reactions were found to take place during r.f. sputtering of copper and led to the formation of the following compounds: CuIn and Cu 4In were formed with indium substrates, Cu 2Sb with antimony substrates and Cu 2Sb and CuIn with InSb substrates. No interface reactions were observed when copper was thermally evaporated onto antimony or InSb substrates.

Changes of the growth morphology in insb crystals pulled under the presence of ultrasonic vibrations

AbstractIn the Czochralski method, the effect of ultrasonic vibrations on the growth of InSb single crystals was investigated by observing the growth morphology. Remarkable changes which ultrasonic vibrations brought about were: (1) the crystal diameter, (2) the width of the facet region and (3) the inclined angle of non‐facet interfaces near the facet region for the (111) plane. After introducing vibrations, the crystal diameter decreased smoothly with growth time. However, both the facet width and the inclined angle reached each minimum value after 5 to 7 min regardless of the magnitude of vibrational output powers from 30 to 90 W, and they were in roughly proportional relation with each other. The change rates of crystal diameter and of facet width increased with vibrational powers. The decrease of crystal diameter was known to result from the rise of the melt temperature, which was brought by both the mixture of the melt and the thermal energy transformation due to ultrasonic vibrations. The change of facet width depended upon the melt flow itself in addition to the temperature rise.

Programming of crystal diameter in Czochralski growth by a cooling plot: Application to InSb

It is shown, that under thermal “stiffness” conditions, the dimensions of a crystal grown by the Czochralski method may be programmed by a cooling plot. The cooling plot is calculated from the measured longitudinal and radial thermal gradients, involving also the melt-to-solid densities ratio. Utilization of the principle could save the need for sophisticated expensive automatic diameter control systems. In the present work the principle was successfully applied to the growing of InSb single crystals of diameters around 2cm.