On the synchronizing band of a rational harmonic injection locking

 Compared with the harmonic injection locking(HIL),a rationai harmonic injection locking (RHIL)can make the circuit even simpler and more flexible.A common formula for the synchro- nizing band ⊿ω(s_m)max of the RHIL is derived and analysed in this paper.The result shows that the formula given by Schmideg(1971)is only its special case.A method for extending the RHIL\'s synchronizing band with full-pass network is presented.Using the method,a 2/3 injection locking VHF divider consisting of the FZ1C,a type of IC,is developed,with a stability factor n=⊿f_((3/2)max)/ ⊿f_((-40-+85℃))≥4;while for the original circuit,n≈0.6.Thus,the RHIL may be of more practical value in applications.     

The diffusion of Zn in GaAs at low temperature

The diffusion of Zn into GaAs at low temperature has been investigated. The experiments are carried out in an evacuated and sealed quartz ampoule using ZnAs₂ as the source of Zn. The relation among the junction depth (X _j), the time (t) and the temperature (T) of diffusion has been investigated. It is found that the sheet resistance (R _s) of diffusion layer increases asX _j decreases. The surface concentration (C _s) decreases as 1/T increases, and mobility (μ) decreases asC _s increases. TheC _s versus 1/X _j·R_s) are plotted, the results are thatC _s increases as 1/X _j ·R _s ) increases. This is a simple method for determiningC _s of the multiple GaAs/GaA1As epitaxial layer. The mechanism of Zn diffusion in GaAs and InP is discussed. This process has been applied to fabricate GaAs/GaAlAs double heterojunction light emitting diodes and an output power of 2—4mW is obtained, the series resistance is 3—5Q.     

Lock-in-phase analysis of n-GaAs photoreflectance spectra

The phase dependence of the photoreflectance signal in the region of the E ₀ transitions in GaAs samples has been investigated using the two-channel lock-in technique. The spectral components and their synchronous phases have been established as the result of a detailed analysis of the photoreflectance spectra. The time constants of the photoreflectance signal have been calculated for the observed single-component and multicomponent photoreflectance spectra. The time dependence ΔR/R _j∼±exp(−t/τ _j) of the photoreflectance signal is due to the delayed reaction to the photomodulation of the electric field in the region of the semiconductor surface or interface. Fiz. Tekh. Poluprovodn. 32, 272–277 (March 1998)     

The influence of supercooling on the liquid phase epitaxial growth of inas1−xsbx on (100) GASB substrates

The growth by liquid-phase epitaxy of InAs_1−x Sb _x (x = 0.08-0.16) on GaSb was accomplished by using melts of constant arsenic concentration x _As ^L = 0.014. The study of the influence of the degree of supercooling ΔT on the crystal growth was investigated. The strong tendency of the In-As-Sb liquid to dissolve the GaSb substrate was resolved by using high ΔT (20-30° C) for layers having a positive lattice-mismatch Δa/a more than 1.5 x 10⁻³. As positive lattice-mismatch becomes smaller, a larger supersaturation is required to control the substrate dissolution. But owing to the bulk nucleation which restricts the supercooling ΔT at values near 30° C, the growth of epitaxial layers with small lattice-mismatch (until - 5 × 10⁻⁴) was achieved only from time to time. It was observed that an increase of ΔT increases the concentration of antimony in the epilayers and hence leads to the lattice-mismatch. The dislocation etch pit density was found to be only dependent on the lattice-mismatch. The thickness of the grown layers is proportional to ΔT xt ^1/2 with a factorK = 0.025 μm . °C⁻² . s^−1/2     

Nature of E c −0.37 eV centers and the formation of high-resistivity layers in n-type silicon

The DLTS and Van der Pauw methods are used to investigate the production of E _c −0.37 eV centers responsible for the formation of high-resistivity layers in n-type Si irradiated with electrons and annealed in the temperature range 80–320 °C. An analysis of the experimental data leads to a conclusion as to the composition of the E _c −0.37 eV centers ([V-O-C]) and to the conclusion that their formation is stimulated by a flux of interstitial atoms away from the interface into the interior of the semiconductor during annealing accompanied by the reactions: 1) I+C_s→C_i,C_i+[V-O]→[V-O-C] (dominant reaction); 2) I+V ₂→V,V+[C-O]→[V-O-C]. Fiz. Tekh. Poluprovodn. 31, 993–997 (August 1997)     

The principle of design for double injection Ge magneto-diode

 design principle is propose for long.P~+IN~+Ge magneto-diode with a high surface recombination region on one side.The optimal relation is established for design among its length l,depth d,width w and resistivity p: where ⊿T is the maximum permissible temperature rise of the chip,R_(th)the thermal resistance of the header,I_o the forward current of the diode.     

Study of Zn,Zn−Cd diffusion in In x Ga1−x As

 In this report,the diffusion of Zn,Zn-Cd in In_xGa_(1-x)As is investigated using ZnAs_2 and ZnAs_2+Cd as diffusion sources. The effect of the diffusion temperature,diffusion time,a variety of the diffusion source and composition x of the material on the relation of the(X_j-t~(1/2))are given.The diffusion velocity X_j~2/t of Zn in In_xGa_(1-x)As is faster than that of Zn-Cd in In_xGa_(1-x)As,and at 500-600℃,the surface acceptor concentration is from 1×10~(19)to 2×10~(20)cm~(-3),which is higher than that of Zn in InP.Reduction of contact resistance by use of In_xGa_(1-x)As contact layer for 1.3μm LED can be expected.     

Exciton characteristics of intercalated TlGaSe2 single crystal

It is shown that lithium-ion intercalation of TlGaSe₂ single crystal leads to a shift of the exciton peak associated with the direct edge toward longer wavelengths (ΔE=15 meV at 5 K). As a result, the temperature shift of the exciton peak in TlGaSe₂(∂E ^ex/∂T) decreases more than twofold in absolute value to −1.1×10⁻⁴ eV/K at 20≲T≲105 K and −0.25×10⁻⁴ eV/K at 5≲T≲20 K. Lithium-ion (Li⁺) intercalation of TlGaSe₂ has almost no effect on the energy position of the exciton associated with indirect transitions. Fiz. Tekh. Poluprovodn. 32, 145–147 (February 1998)     

Fast neutron radiation damage effects on high resistivity silicon junction detectors

P ⁺ −n ^{−n +} silicon radiation detectors made of high resistivity Si material (ρ ≥ 2 kΩ-cm) were irradiated to a neutron fluence of a few times of 10¹³ n/cm². Dependence of detector leakage current, reverse bias capacitance, and effective doping concentration of the Si substrate on the neutron fluence have been systematically studied. It has been found that the detector leakage current increases linearly with neutron fluence in the range studies, with a damage constant of α = 9 × 10⁻¹⁷ A/cm(ΔI = αΔAϕ_n @#@), and the C-V characteristics of detectors irradiated to ϕ_n > 10¹² n/cm² become frequency dependent. Models using several defect levels in the band gap are proposed to describe the frequency dependent C-V effects and the electrical field profile after high neutron fluence irradiation. This research was supported by the U.S. Department of Energy: Contract No. DE-AC02-76CH00016.     

Luminescence and electrical properties of InGaN/AlGaN/GaN light emitting diodes with multiple quantum wells

Luminescence spectra of light-emitting diodes based on InGaN/AlGaN/GaN heterostructures with multiple quantum wells are studied for currents in the range J=0.15 μA-150 mA. The comparatively high quantum efficiency for low J(J _max=0.5–1 mA) is a consequence of a low probability for the nonradiative tunnel current. The current-voltage characteristics J(V) are studied for J=10⁻¹²–10⁻¹ A; they are approximated by the function V=ϕk+mkT· [1n(J/J ₀)+(J/J ₁)^0.5] + J · R _s. The portion of V∞(J/J ₁)^0.5 and measurements of the dynamic capacitance indicate that i-layers adjacent to the active layer play an important role. The spectra are described by a model with a two-dimensional density of states with exponential tails in multiple quantum wells. The rise in T with increasing J is determined from the short-wavelength decay of the spectrum of the blue diodes: T=360–370 K for J=80–100 mA. An emission band is observed at 2.7–2.8 eV from green diodes at high J; this band may be explained by phase separation with different amounts of In in the InGaN. Fiz. Tekh. Poluprovodn. 33, 445–450 (April 1999)     

Effect of successive implantation of Ag+(Cu+) and Xe+ ions on the recombination properties of CdxHg1−x Te crystals

The effect of successive double implantation of Ag⁺(Cu⁺) and Xe⁺ ions on the recombination properties of Cd_xHg_1−x Te (0.2<x<0.3) crystals has been investigated. It is shown that after implantation of ions of one chemical element, followed by diffusion thermal annealing at temperatures below 150–200 K, recombination through local levels lying 30±5 meV below the conduction band bottom dominates. Successive double implantation of Ag⁺(Cu⁺) and Xe⁺ ions followed by diffusion thermal annealing changes the course of the temperature dependence of the lifetime of the nonequilibrium charge carriers. It was determined that for Cd_xHg_1−x Te crystals with x⋍0.20–0.25 in the temperature interval 700–200 K the lifetime of the nonequilibrium charge carriers is low (τ<0.15 μs) and does not depend on the temperature. For Cd_xHg_1−x Te crystals with x⋍0.3 recombination of nonequilibrium charge carriers occurs through two types of levels: in the temperature range 140–200 K — deep levels E _t1⋍E _c −51 meV and at lower temperatures (77–140 K) — through shallower levels E _t2⋍E _c −(16±2) meV. Fiz. Tekh. Poluprovodn. 31, 786–789 (July 1997)     

Characteristic features of the accumulation of vacancy-and interstitial-type radiation defects in dislocation-free silicon with different oxygen contents

The formation of the main radiation defects in silicon (A and E centers, C _i -C _s and C _i -O _i complexes) in dislocation-free crystals and crystals with a low dislocation density (N _D ≃1×10⁴ cm⁻²) have been investigated as a function of the oxygen density N _O. The characteristic features of the accumulation and annealing of radiation defects observed in dislocation-free silicon are interpreted taking into account the presence of interstitial inclusions in the volume of such crystals. It has been determined that the gettering properties of the inclusions depend in a complicated manner on the oxygen concentration and are most obvious when N _O⋍3×10¹⁶ cm⁻³. Fiz. Tekh. Poluprovodn. 31, 405–409 (April 1997)     

Self-Testing Embedded Borden t-UED Code Checkers for t = 2 k q − 1 with q = 2 m − 1

Borden codes are optimal nonsystematic t-unidirectional error detecting (t-UED) codes. A possible method to design a Borden code checker is to map the Borden code words to words of an AN arithmetic code and to check the obtained words with an appropriate AN code checker. For t = q − 1 with q = 2 ^m  − 1 we show how this method can be modified such that the Borden code checkers achieve the self-testing property under very weak conditions. It is only required that no checker input line gets a constant signal and that the Borden code words occur in a random order, making the proposed checkers very suitable for use as embedded checkers. Based on these checkers it is then possible to design embedded Borden t-UED code checkers for t = 2 ^k q − 1 with q = 2 ^m  − 1.

Investigation of the Mθ/G/1/m system with service regime switchings and threshold blocking of the input flow

The M^θ/G/1/m queueing system with the group arrival of customers, switchings of service regimes, and threshold blocking of the flow of customers is studied. The input flow is blocked if, at the instant of the successive customer service start, the number of customers in the system exceeds specified threshold level h. If, at instant t of the customer service start, number of customers in the system ξ(t) satisfies the condition h_i < x(t) \leqslant h_{i + 1} (i = [`(1,r)] )h_i < \xi (t) \leqslant h_{i + 1} (i = \overline {1,r} ), then the service time for this customer corresponds to distribution function F _i (t). At 1 ≤ ξ(t) ≤ h = h ₁, the service time for a customer is distributed according to law F(t) (basic service time). The Laplace transforms for the distribution of the number of customers in the system on the busy period and for the distribution function of the busy period are found, the mean length of the busy period (including the case m = ∞) is determined and formulas for the ergodic distribution of the number of customers in the system (including the case m = ∞) are obtained. An effective algorithm for calculation of the ergodic distribution is proposed. The recurrence relations of the algorithm are not explicitly dependent on m.     

Effect of In doping on the kinetic coefficients in solid solutions of the system PbzSn1−z )0.95Ge0.05Te

In the quaternary solid solutions (Pb_zSn_1−z )_0.95Ge_0.05Te (z=0.35 and 0.40) the effect of addition of indium (in amounts of 5–20 at. %) on the temperature dependence of the electrical conductivity σ, Hall coefficient R, Seebeck coefficient S, and Hall mobility u is investigated on samples prepared using powder technology. We found a monotonic dependence of the hole density p on the indium content N _In with a tendency toward saturation at a level p _max≈3×10²¹ cm⁻³, an abrupt drop in the mobility in samples with p≈p _max, and changes in the character of the temperature dependences R(T) and σ(T). We show that these peculiarities in the behavior of the kinetic coefficients can be interpreted in terms of quasilocal indium impurity states against the background of the valence band spectrum (with energy ɛ _In∼0.3 eV) and resonance hole scattering into these states. Fiz. Tekh. Poluprovodn. 32, 1190–1193 (October 1998)     

Constant geometry split-radix algorithms

The split-radix algorithm (SR) is a highly efficient version of the successive doubling method (SD). Its application to the Fourier transform results in an algorithm that brings together the advantages of the radix 2 and radix 4 algorithms. In this work we present the generalization of the method that leads to the SR algorithm in the FFT and the implementation of a constant geometry (CG) version of it. In particular, we develop a CG algorithm of the successive doubling method that factorizes a sequence of lengthN intop sequences of lengthN/r and into (r−p)r of lengthN/r ²(r≥2, 0<p<r). After this, the method is generalized for its application to SRr, r ²,...r ^u algorithms, that is, to those based on the factorization of a sequence of lengthN intop ₁ subsequences of lengthN/r, p ₂ r of lengthN/r ²,...,p _u r ^u−1 of lengthN/r ^u (p ₁+p ₂+...+p _u =r). The results are applied to the implementation of a pipeline with identical stages and to a processor column. This work was supported by the Ministry of Education and Science (CICYT) of Spain under project TIC-92-0942-C03.     

Determination of the valence-band offset and its temperature dependence in isotypic heterojunctions p-AlxGa1−xAs/p-AlyGa1−yAs from C-V measurements

The isotypic heterojunctions p-Al_xGa_1−x As/p-Al_yGa_1−y As, grown by MOVPE on n-GaAs substrates, have been investigated by the voltage-capacitance method at temperatures ranging from 300 to 100 K. To determine the valence-band offset ΔE _V and the built-in charge in the heterojunction, the Poisson equation was solved numerically on a nonuniform coordinate grid. The incomplete ionization of the acceptors and the different magnitude of the permittivity in different layers of the heterostructure were taken into account in the calculation. It was found that for a p-Al _0.2 a_0.8As/p-Al _0.5 Ga_0.5As heterojunction ΔE _V at room temperature is 39% (113 meV) of the total gap ΔE _g and decreases monotonically to 35% at T=120 K. Fiz. Tekh. Poluprovodn. 33, 940–944 (August 1999)     

Current transport in porous p-Si and Pd-porous Si structures

Mechanisms are investigated for current transport in porous p-Si and Pd-p-por-Si structures in the temperature range 78–300 K. It is shown that at 78 K drift transport is decisive, with the participation of deep traps with a concentration N _t≈1.3×10¹³ cm⁻³. At higher temperatures the diffusion mechanism takes over, with I∼exp(−qV/nkT) and n=10–20. Relaxation processes for the reverse current and photocurrent (ascending branch) have a delayed character (up to t⋍100 s) and are determined by the effect of traps at a depth E _t=0.80 eV. The temperature behavior of the photocurrent (without a bias) is connected with recombination at a level E _r=0.12 eV, and its value essentially depends on the contribution of the basal region of the diode structure. Fiz. Tekh. Poluprovodn. 32, 1073–1075 (September 1998)