In semiconductor crystals, elastic deformation causes a shift of the energy levels and a change in the spectrum of the charge carriers. As a result of this, a deformation of p-n junctions causes a noticeable change in the height of their potential barrier and a corresponding change in the forward and back currents. Under these conditions, the smallness of the deformation-potential constants causes a change in the direct current of the p-n junction to be observed for fairly high values of the static pressure and relative deformation (see [1]). However, the effect of a variable deformation is much easier to detect. Moreover, a variable elastic deformation may influence the noise characteristics of semiconductor devices. The present work presents the results of investigating the effect of ultrasonic deformation on the operation of semiconductor devices under conditions when the deformation period was substantially longer than the relaxation time of the charge carriers. Here the ultrasonic deformation may be treated as being quasistatic, while the observed conversion of ultrasonic waves to electrical waves may be considered within the framework of the deformation potential. Measurements were performed of the amplitude and amplitude-frequency dependences of acoustoelectric conversion in semiconductor devices. The ultrasonic deformation was created by a piezotransducer having a known amplitude-frequency response (AFR) that was rigidly glued to a glass sound conductor. The sample was glued to the opposite side of the sound conductor. An alternating voltage Vtr having a frequency of 0.05-1.5 MHz was applied to the piezotransducer. In all of the investigated samples, a voltage U ^ at the ultrasound frequency was recorded in the output circuits. The minimum power of the ultrasonic waves at which acoustoelectric conversion was observed in our work is estimated at 5 mW. Along with 538UN1 and K574UD1A microcircuits in a metal-glass housing, MP37 transistors were used as samples. The choice of samples was based on matching the acoustic impedance of the sound conductor to the sample. It should be noted that when the same types of microcircuits in plastic housings were used, the voltage Uw was substantially lower, and in a number of cases it did not exceed the voltage of the intrinsic noise. In accordance with [1] the value of the total change in collector current accompanying static deformation of p-n junctions is proportional to the transistor gain k and to the change in base current. This relationship was used to find the amplitude dependences of the alternating voltages at the output of microcircuits connected according to a noninverting amplifier circuit; the results are shown as an example in Fig. 1. The dependences have been plotted for ultrasound frequencies/ = 100 kHz (curve 1 is for a gain k = 103; curve 2 is for k = 102; and curve 3 is for k = 10). Analogous dependences were also obtained for transistors. It follows from the figure that the tangent of the slope angle of the dependences representing the acoustoelectric conversion U ^U ^) is determined by the gain k. The measurements which were performed of the dependences of the voltages U^ of the converted waves on the direct current Jb through the base revealed the following peculiarity: at negative currents exceeding 0.4 mA, U^ remained practically constant, while for positive currents it increased linearly with increasing current Jb right up to transistor saturation. The variations of UM for microcircuits evidently did not exceed several percent due to the presence of built-in current sources. Since acoustoelectric conversion may be one of the factors determining the level of excess noise in semiconductor devices, we made a comparison between the spectrum of the electrical noise arising as a result of the conversion and the original acoustic noise. The acoustic noise was simulated by a piezotransducer and a sweeposcillator whose frequency was varied within a specified range. The recording was carried out by means of an S474 spectrum analyzer. With allowance for the gain reduction of the devices at high frequencies, the two spectra were practically no different from one another. © 1989 by Allerton Press, Inc.

In this paper, the mechanisms of laser ultrasound response formation in monocrystalline silicon are discussed. The ultrasound waves in the test specimen were generated with laser pulses of two different wavelengths and registered with a piezoelectric transducer. The amplitude of the measured signal was found to be a nonlinear function of the laser radiation intensity. It was shown, that the observed nonlinearity is related to the features of optical absorption and thermoelastic sources formation in the material. A simple model taking into account temperature dependencies of the thermal conductivity and thermal expansion coefficient was developed. An excellent agreement between experimental and simulation for different wavelengths was demonstrated.

Microplasma breakdown luminescence of InGaN/GaN heterostructures in different types of high-power light emitting diodes is studied. It is shown that the spectrum of the breakdown luminescence, the luminescence onset voltage, the current in the first microplasma, and the number of microplasmas for a fixed voltage all correlate with the density of critical extended defects, the luminous flux, and the uniformity of current flow, and are determined by the type of substrate (Si, SiC, Al2O3).

Microplasmas breakdown of the InGaN/GaN heterostructures of different types of high-power light-emitting diodes is studied. It is shown that microplasma parameters, connected with reliability and such fabricating technology of the InGaN/GaN heterostructures as substrate material - Al2O3, SiC or Si, which determines the density of the critical extended defects, light flux, homogeneity of current spreading.

A non-destructive method for the technological control of the structure defects in SiO2 + Si wafers by measuring the internal friction background difference on the nearby harmonics f1 and f2 after mechanical and heat treatments.

The measuring of internal friction background after mechanical, heat treatments gives information about the changing of defect nanostructure and the thermoelastic strains fields in Si + SiO2 plates. The broadening of internal friction maximums represents the relaxation process of structural defects new types.

It is shown that the probable mechanism of fluctuations of surface and three-dimensional EL intensity distribution of light-emitting heterostructure is occurrence and burning-off of local pipes in areas, which because of the nonuniform distribution of indium in InxGa1-xN solid solution and influences of dislocation system have greater conductance.

The carbon nanotubes and polypropylene total deformation consists of elastic and inelastic constituents ε∑ = εE + εIE. Inelastic deformation εIE is conditioned motion of dislocations. Elastic deformation εE takes a place "instantly". The absolute value of the elastic module E, elasticity limit σE, inelasticity limit σ0.2, ultimate stress limit σS of the composites carbon nanotubes 5% + polypropylene, carbon nanotubes 0,5% + polypropylene, carbon nanotubes 0,1% + polypropylene were determined.

A gas discharge is observed in light-emitting diodes based on an InGaN/GaN structure for currents significantly greater than the operating currents, under conditions of considerable self-heating with formation of blisters in the polymer case of the LED, localized above the emitting surface of the heterostructure. In this case, we detected threshold appearance of intense emission in the red and infrared ranges of the spectrum. We show that the major mechanism for this emission is formation of a gas-discharge plasma as a result of non-oxidative thermal degradation of the polymer, surrounding the heterostructure and current carrying contacts.

It was shown that in the GaAsP/GaP and InGaN/GaN heterostructures during current passage redistribution of electroluminescence intensity on the structure surface takes place simultaneously with radiation of acoustic emission. Local (on surface area) fluctuations of electroluminescence intensity are observed together with general degradation of electro-physical parameters.

Сomplex researches of light-emitting structures based on А3В5 compounds have been carried out. It has been shown that at current loading exceeding the acousticemission threshold, there arises a change in the electroluminescence intensity, fluctuation of current and light. It has been ascertained that natural ageing leads to a general improvement of some practically important parameters of light-emitting structures, in particular to increase of maximal admissible currents and reliability.

The features of mass transfer of indium in high-resistance CdTe crystals under nanosecond irradiation of the In-CdTe structure by laser pulses have been studied and analyzed. The mass transfer coefficients are determined and the average transfer rate of the indium atoms in CdTe under irradiation is evaluated. It is assumed that the concentration diffusion of indium in CdTe and the transfer of impurity atoms by the front of the laser-induced shock wave are not dominant mechanisms of mass transfer under dynamic doping. The most probable process, which provides the formation of the inverse layer in the surface region of the CdTe crystal under nanosecond laser irradiation of the In film, is an transfer of interstitial In atoms due to the thermal fluctuation jumps under the action of the driving force of the thermoelastic stresses and temperature gradient.

In work the influencing of variable deformation ε was researched on elastic and inelastic characteristics: elastic module E and internal friction (IF) of carbon nanotubes and polypropylene; Ti ВТ1-0 alloy.

In work it is shown, that in the GaAsP/GaP and InGaN/GaN heterostructures at current passage simultaneously with operation of acoustic emission sources take place a redistribution of electroluminescence (EL) intensity on a structure surface, are observed local (on areas of surface) and integrated fluctuations of EL intensity and current.

In operation the analysis of dynamics of an acoustic emission that accompanies with degradation and local processes of a relaxation and a defect formation in locally-is non-uniformly thermostrained heterostructures InGaN/GaN and GaAsP/GaP at step-by-step magnification of a direct current is lead. It is shown, that dynamics ÀÅ is well coordinated with the basic guesses — ÀÅ is the chaotic relaxation process determined in time, parameters ÀÅ depend on quantity of change and velocity of change of a level of the exterior fixed loading, quantity of the same sources ÀÅ activated by this influence during time of its activity, and also a variance of some parameters of these sources AE.

The question of a relaxation of superficial mechanical pressure after a pulse laser irradiation in complex semiconductor compounds which is accompanied by formation of the difficult acoustic response is considered. In work it is shown, that the laser-induced melting threshold of single and poly- crystals can be established on dependence of amplitude and (or) energy of the acoustic response — the laser pulse intensity, in particular by the given method establishes melting thresholds of single crystals GaAs, CdTe and S³ at nanoseconds pulse irradiation of ruby and neodymium laser. It is established, that at nanoseconds laser pulse irradiation is possible registration only discrete highenergy acoustic emission due to a fast relaxation created elastic and thermoelastic pressure.

Failure of internal mechanical pressure at origin and movement of dislocations in processes of fast degradation and defect formation in LED and semiconductor lasers lead to occurrence of acoustic emission (AE) - to the phenomenon of radiation of pulse spontaneous acoustic wave's noise character. This failure of internal mechanical pressure in local volumes with occurrence AE is possible only at action of external fields (influences) of the certain physical nature, in our case - non-uniform fields of the thermomechanical pressure created by a constant direct current. In work were investigated n+-n-p- structures basis on the GaP:N, GaP0,85As0,15:N, Zn-O, InGaN/GaN and p+-p-n- structures basis on the Ga0,7Al0,3As and Ga0,65Al0,35As. During step-by-step increase of a current 10-25 multiple change of AE occurrence threshold and a destruction threshold of structures was revealed at natural ageing structures after 6̇108 s. For some samples of structures at low temperatures (77) AE occurrence threshold came nearer or even corresponded to a destruction threshold. The given effect explains gradual saturation of dislocations by atoms of impurity with formation of Cottrell cloud, that considerably lowers their mobility and increases activation energy and accordingly a AE occurrence threshold

It is shown, that in heterostructures based on A(3)B(5) compounds acoustic emission occurrence, current and light fluctuations, evolution electroluminescence spectrums, current-voltage characteristics degradation occur simultaneously and has the common origin.

In light-emitting A(3)B(5) structures, a correlation between the process of acoustic emission (AE) occurrence and fluctuations of the electroluminescence intensity and current has been revealed, which indicates a common mechanism of their origin. It has been shown that in these structures, including InGaN/GaN structures with quantum wells, the probable reason of it is the consecutions of physical processes leading to correlation of three various pulse sequences. Revealed is the presence of several activation mechanisms (sources) of AE, which are corresponded by various scenarios and physical processes of local reorganization of material structure with different values of the activation energy.