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Studies have shown that in the local approximation, the behavior of electrical properties of semiconductor surfaces, interfaces, processes of current flow and charge transport, as well as the majority of technological processes on the nano-level satisfy all properties of chaotic systems. In the local approximation, the dependences of the electrophysical properties of objects and geometry of technological...
Study results of frequency properties of sapphire and 4H-SiC{0001} silicon carbide substrate show availability of anisotropy and dispersion of effective dielectric constant ??(f). In both cases a value of ??(f) decreases with frequency f increasing. For a sapphire substrate the dispersion (??(f=3.3 GHz)=9.32 and ??(f=37.6GHz)=8.62) is 7.5 percent, anisotropy is lesser than 0.5 percent. For 4H-SiC...
Three-dimensional modeling of electrostatic metal-semiconductor contact with Schottky barrier has fully confirmed the presence of the experimentally observed extended halos with low contact difference of potentials of the surface around the contacts. The results show that changes in surface potentials around the contacts are caused by the spread of electric charge of the space charge region on a sufficiently...
It is shown that electrophysical property fractality (for example, ??=??(l,d)) of a heteroepitaxial AlGaN/GaN structure with two-dimensional electron gas has a strong influence on field effect transistor linear model. In the present work influence of fractality on inner elements values of transistor equivalent circuit is described. It is necessary to take this influence into the account during design...
It is shown that in the local approximation, the fractality of electrical properties of the 2D-channel has strong influence on the behavior of static CVC of the drain-source channel of AlGaN/GaN HEMT. An increase of the linear resistance ??(l,d) with decreasing length l and width d of the channel down to the values less than the limit of the local approximation L leads to a slower growth of the drain...
It was shown that in the region of direct current with Uf>qϕb there is the negative resistance part at static VAC of rectifying metal-semiconductor junctions. Theoretical calculation reveals that negative resistance on the direct brunch of VAC is caused by potential step in order to transfer ballistic electrons through a thin base (∼0.1 um) of the diode. Analysis of transferring time τT(E) and...
Gunn diode operation based on two-temperature model was investigated in (10…50) GHz frequency band. It is shown that with a (1.0…1.8) μm active layer's length and with the positive linear gradient of electron density distribution in the diode's base, Gunn diodes can operate with efficiency of 6% at the first harmonic.
It is shown that increasing of full width W of the sink-source channel in Al30Ga70N/GaN HEMT at the expense of the increase of n (a number of sections) results to decreasing of Gmax(F) and H21(F). Therefore, amplifying limit frequencies of current Ft and power Fmax also decrease. Ft and Fmax decrease at the increasing of n is related with increasing parasitic parameters of Al30Ga70N/GaN HEMT.
With the use of AFM it has been demonstrated one of the possible ideal surface states of the epitaxial layer n-InP, which allows obtaining the metal-semiconductor contacts in submillimeter range with a low Schottky barrier height ϕb<0.5 eV, the ideality index n <1.07, and series resistance RS <10 ohm. It was shown in practice, that the semiconductor surface required to obtain quality metal-semiconductor...
Obtained results show, that used modes of positron annealing of low-frequency (1–3 GHz) HEMT lead to rising of power and current gains (Gmax and H21 respectively). The value of cutoff frequency Ft does not decrease, and the Fmax raised. According to S-parameters of low-frequency (1–3 GHz) HEMT at high-frequency (20–40 GHz) range, one can see parameters degradation of the used construction. To improve...
It was shown that profile optimization of substrate doping of Schottky multiplier diode allows not only increasing significantly the capacity overlap coefficient KCB>4.5, but also providing the minimum value of leakage current over the range (0–10 V) of reverse biases. With the use of AFM has been shown one of the possible statistically ideal states of the epitaxial n-GaAs surface, which allows...
It is shown that in case with uniformly doped GD base there is no way of developing high-field domain. Instead of this negative-charged accumulation layer appears and moves from cathode to anode. Simultaneously appears an excess of electrons in anode region of the high-field. Spontaneous excitation and relaxation of electrons in this region probably leads to white noise generation within quite wide...
The lateral dimension effect of GaAs channel epitaxial layers of drain-to-source (D-S) MEFSET appears depending on resistivity ρ(l, d) of its linear dimensions: length l and width d. Depending on the manufacturing technology for the specified length l, every material is characterized with its optimal width of d channel, when a minimum carrier scattering is observed, which influences greatly on MEFSET...
It was shown that the built-in electric field, formed by contact periphery, influences greatly on the effectiveness of photoelectric transducers (PT) made on the basis of metal-semiconductor (M-S) contacts. Enhancement of this field results in increasing voltage sensitivity on >50% and current sensitivity on more than 50 times of these PT's. As a result a physical model of electric field distribution...
Impedance and operating temperature of Gunn diodes (GD) used in the modified mode (MM) are the same as in the transit-time mode. The MM may be realized in GD with the thin base layer (L<1.5μm), where the value of strong field domain equates, or exceeds, the base length. Extended frequency range and high efficiency of GD working in MM have allowed using GD efficiently in the following types of GD...
It was shown [1, 2] that in the local approximation fractal properties of 2D-electron gas AlGaN/GaN of het-erostructures, determining the dependence of resistance per unit length ρ on length l and width d of the HEMT-transistor drain-to-source channel, significantly influence on its instrument characteristics: drain-to-source resistance RSD, thermal breakdown resistance UH and transconductance GM...
It was shown that modern AFM methods of controlling geometry and physical parameters of semiconductor InP/InGaAs/InP heterostructures can be successfully applied in manufacturing of modern UHF DHBT-transistors with narrow base (< 100 nm). Operational control of geometric and physical parameters of heterostucture in intervals between carrying out technological operations allows controlling more...
The result showed that consideration of n-GaAs epitaxial layer fractal properties allows one to obtain better instrument characteristics in the process of engineering and manufacturing of 0.01–1 GHz low-noise MOFSET of average power 100–500 mW: smaller noise coefficient and higher gain coefficient Cg>25 dB (transconductance of GM>180 mS/mm) at a longer gate Lg=1 microns. The results thus indicated...
It was found that as a result of self-affine (fractal) geometry of GaN / AlGaN hetero-epitaxial layers, electrons in DEG-channel HEMT-structures move not in 2D, but in 3D plane. It leads to additional scattering of electrons and the linear resistance depends on DEG-channel source-drain HEMT-transistor size. Self-affine properties of the DEG-channel depend on self-affine (fractal) geometry of GaN buffer...
It has been found that the screening electric field El located at the periphery of the metal-semiconductor contact with Schottky barrier and penetrating to the contact, depends on contact diameter D and prevents electrons from direct motion, as well as strengthens the electric field of the contact. The impact of El on forward-bias regions of volt-ampere characteristic results in almost total absence...
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