SCIENTIFIC ABSTRACT LYTOVCHENKO, V. G. - LITOVKIN, M. V.

• Document Type: CREST
• Collection: Scientific Abstracts
• Document Number (FOIA) /ESDN (CREST): CIA-RDP86-00513R000930210004-2
• Release Decision: RIF
• Original Classification: S
• Document Page Count: 100
• Document Creation Date: November 2, 2016
• Document Release Date: March 13, 2001
• Sequence Number: 4
• Publication Date: December 31, 1967
• Content Type: SCIENTIFIC ABSTRACT

TO V C?
S1185
26591 1601005100310061020
7o 0 D274/D303
AUTHORS: Prymachenko V. Ye L
-4itovchenko, V.G., Lyashenko,
V.I. and SrLitko' O:V.
TITLE: The study of fast: and slow electron states on a
germanium surface
PERIODICAL: Ukrayins1kyy fizychnyy zhurnal, v. 5, no. 3, 1960,
34.5-356
TEXT: The effect of an external electric field is studied on the
dark conductivity (the field effect) and an the surface recombina-
t-Lon of thin germanium plates in vacuo. The field effect was inves-
tigated at a d.c. voltage, as well as by applying rectangular pulses;
this made it possible to detenrine separ.Ltely the parameters of the
fast and slow surface states. The method of investigation used is
more advantageous than earlier methods; in particular, it permits
studying all the surface states on a sing,12 specimen. 'Elie size of
the specimens was aPproximately 1.5 x 0.5. x 0.015 cm. Me specimens
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The study of fast and slow electron...
S/185/60/005/003/006/020
D274/D303
were treated with CP-4 and, after measurements, with boiling H202,
The germanium plates were p-type with specific resistance 40 - 50
Ohm. The specimen served as one plate of a capacitor to which a
d.c. voltage of 2500 v was applied ar. well as an a.c. voltage (rec-
tangular pulses). The dark conductivity cr was measured by a com-
pensation method. The change in conductivity AO" (following the
application of the rectangular pulses), was measured by a special
circuit. The rate of surface recombination was determined by the
effective relaxation time 'r of the photoconductivity, following
the illumination of the- middle part of the specimen by the rectangu-
lar pulses of light.. The relaxation of the photo;::urrent followed an
exponential law. A diagram is given of VI-Le circuit used for the in-
vestigation. Curves are given for Ao- as a function of the charge
Q induced on the germanium surface. The presence of a minimum on
the experimental curve A(r(Q) permitted determining-the surface
potential Y for each Q. The total su@face potential reaches 15 kT/e
1-'-4 0.38 eV., i.e. it is approximatelir ecpial to half the width of
the forbidden germanium zone. Furthe@, the field effect makes it
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26591 S/185Z60/005/003/006/020
The study of fast and slow electron... D274/0303
possible to deterimine the charge Q. in both fast and slow states,
(Qs z Q - Qo, where Q. is the space charge). Yhe surface charge in
fast states changes relatively little for small Y, whereas for large
Y it changes rather sharply. The dependence of Q. on Y leads to the
interpretation of the energy levels (discrete vs. co-atinuous). The
authors assume discrete interior levels; this assumption is support-
ed by the results of recombination measurements and is also in agree-
ment with A. Many's results (Ref. 21: J. Phys. Chem. Solids. 8, 87,
1959). Therefore, the results obtained from the field effect for
the fast states are interpreted by the authors by means of a model
of four discrete levels, whose parameters are given in a table; for
the slow states, two discrete levels are assumed. The chat -gc of
the slow states is much greater than that of the fast states. Henc
the slow states are of' basic importance in screening the constant
external field. 'Furtherthe dependence of the rate oil surface re-
combination s on -the surface potential Y is plotted and discussed.
The East levels are responsible for the recombination; two or even
three such levels can substantially contribute to it; but, in gen-
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The study of fast and slow electron... D274YD303
eral, one of the fast levels is predominant in surface recombination.
The values of the capture cross-sections of electrons and holes are
given in the table. The measured values of the parameters of the
surface levels depend on the etching method (by means of GF-4 or by
112,02) and on whether the surfaces were freshly etched or a long
time ago (their previous history); thereby the difference in the
parameters is, however, not as considerable as should have been ex-
pected; the concentration of the fast states, and especially their
recombination capacities show considerable dependence on the pre-
vious history of the specimens. Finally, the presence of an oxide
layer on the germanium surface is considered as definitely estab-
lished; this layer has a complex chemical and polycrystalline struc-
ture. The layer is the main reason for the complex system of sur-
face states of germanium. The slow states are found on the outer
surface of the o>dde, being mainly detemined by adsorbed atoms,
whereas the fast states are on the intei. -face Ge-oxide, being mainly
due to imperfections of structure and eXtraneous atoms. There are
5 figures, 1 table and 36 references: 14 Soviet-bloc and 22 non-Sov-
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26593.
The study of fast and slow electron...
S/185/60/005,/003/006/020
D274/D303
iet-bloc. The 4 most recent references to English-la:nguage publica-
ys. a.Chem.
tions read as follows: E. Harnik. G. Margoninski, Ph-
Oolids, 8, 96, 1959; A. Many, J. Phys. Chem. Solids, 8, 87, 19-59;
P-E. Schlier, H.E. Farnsworth, J. Chem. Phys., 30, 917, 1959; G.A.
Barnes, P.C. Banbury, J. Phys. Chem. SOlidG, 8, 111, L959.
ASSOCIATION: Instytut fizyky All USSR (Physics Institute, 16 Ukr
SSR)
SUBMITTED: November 5, 1959
Gard 515

89276
S11 8Y61/003/001/006/042
.24-14100 (jo43.0#o51r,,116-0) B102 B212
AUTHORS: Litovohenko, V. G. and Lyashenko, V. I.
TITLE% Invel3tigation of the properties of a germanium surface at
different temperatures. I. Amplitude characteristics
PERIODICALj Fizika tverdogo tela, v- 3, no. 1, 1961, 61-72
TEXTt The properties of a real germanium surface at room temperature are
well known, but those at low temperatures have hardly been investigated;
and it is uncertain whether the energy distribution of the surface levels
in the forbidden band is discrete or contiruous. A knowledge of the
temperature dependence of the electron surface-state parameters (E' N, and
the trapping arose sections 0 p and Cn) could clarify this problem, but the
T-functions had to be known for each single surface level in a large
temperature interval. The authors investigated several parameters in the
region of 170-3050K, which are characteristic of the surface properties of
germanium, and this paper reports on the rosults. The experimental method
has been described in Refs. 4, 6, 7. 70-3001& thick n-type Ge specimens of
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Investigation of the properties ... B102XB212
quadratic shape have been investigated; they had been cut in the (110)
plans, and had a resistivity of 20-45 ohm-am (at 3000K), a volume lifetime
of,rocf250-10 3Ksea, and a- 100-200 cm/seo. The following measurements
were mades initial change of the conductivity 66-0 of the specimen due to
fiald pulses (10-6 sea), the change Aw after the relaxation processes;
&-r-2
the change AW3 30 sea after the field had been turned on; the proper t1ime
TP of the short-period relaxation of the field effect, and the proper time
Te of the relaxation of photoconductivity. The dependence of these
quantities upon a constant transverse electric field has been measured
for a number of fixed T-values betweeh 170 and 3050K, and the temperature
deloendence of kinetic characteristios without a transverse field (Et-0)
has been recorded. The results of the measurements are illustrated in
diagrams. Fig. 1 shows A6-- as a function of a charge Q which had been
3 1
induoed on the semiconductor by a constant transverse field for n-type Ge,
nOW5.4-1013 Cm-3 in a vacuum. Fig. 2 shows the initial *oend of the band,
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Investigation of the properties... B102/B212
YO(T), and the work.function 2((T) of different surface states as functions
of temperature. For n-type specimens, Yo changes to negative values with
a decreasing temperature (at T=1750K, Yo4 -5-5 kT/e) but increases for
p-type specimens in the positive range. Measurement of the quantities
AWO and '&'r2 made it possible to determine the mobility of the field effect
(@Lf.e.- 40, /AQi) - Fig. 3 shows the initial mobility P-f.e.0 and the
p
quasi-steady Pf.e.2 as functions of the surface potential Y for various
values of T. The parameters of the fast sbrfaoe levels have been calcula
from experimental data on ttf.e.(Y); results are given in Table 1.
Analogous computations were made for slow surface levels, Table 2 gives the
results. The investigations showed that fast and slow surface levels have
the following in oo4momz They are discrete, show the sume number, and the
concentration of the mean surface levels is about one order of magnitude
smaller than that-of the outer ones. The position of the fast surface
energy levels does not fully agree with that of the slow levels, but this
deviation is less than 2 kT/e. The concentrations of t.*,,je slow surface
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Investigation of the properties ... B102/B212
levels are in all cases 2-4 times higher t1an those of the fast surface
levels.. There are 5 figures, 2 tables, and 38 references: 14 Soviet-bloc
and 24 non-Soviet-bloo.
ASSOCIATIONt Institut fiziki AN USSR Kiyev (Institute of Physics,
AS UkrSSR, Kiyev)
SUBMITTEDt MaY 301 1960
Legend to Tables: 1) Number of specimen 2) surface state; 3) within
24 hr after etching; 4) aged specimeni 5@ within 3 hr after etching.
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LYASHENKO, V.I.
Investigating the properties of the surface of germanium at various
temperatures. Part 2: Kinetics of processes. Riz. tver. tela 3
no.2:73-e$ A 161* (KRA 34:3)
le Inatitut fiziki P11 USSRr Klyev,
(Germanium)

S/181/62/004/004/001/042
B108/B102
AUTHORS: Litovchenko, V. G., Frolov, 0. S., and Pao Shchih-mao
TITIJ!'.. Study of long-period variations in electrical properties of
germanium surfaces
PERIODICALs Fizika tvordogo tela, v- 4, no- 4, 1962, 933 - 845
TEXT: A method of stud@ing surface-sensitive effects in semiconductors is
presented. The basic idea is to examine the long-period relaxation of
conductivity and work function in the case of adsorption. A specific
feature of this method is that not one but two quantities characterizing
the surface space charge are to be determined by experiment, namely, the
surface conductivity and surface flexure of the bands. The results of ex-
periments on the electrical surface properties of n-ty-le germanium were
consistent with theory. The method is therefore reconnended for the
quantitative investigation of catalytic reactions in gases and of the
electrcnics of metal and semiconductor surfaces. The most important
results of this work (numerous numerical data on Ge are given) ha.-ie been
reported at the Voesoyuznoye soveshchaniye po poverkhnosti poluprovodnikov
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Study of long-period variations... B108/B102
(All-Union Semiconductor Surface Conference), Moscow$ June 5 - 6, 1961.
Professor V. I. Lys.shenko, I. I. Stepko, Candidate of Physics and Mathe-
matics, and 0. V. Snitko are thanked for di8cussi:)ns. There are 8 figures,
2 tables, and 27 roferences: 9 Soviet and 18 non-Soviet. The four most
recent references to English-language publications read as followas
J. N. Zemel, R. F. Green. Proc. Int. Conf. Semic., Prague, 549, 1960;
R. F. Green et al. Phys. Rev., 118, 967, 1960; R. F. Green. J. Phys. a.
Chem. Sol. jj, 291, 1960; Amith. J. Phys. a. Chem. Sol. jA, 271, 1960s
G. Dorda. Czechoslov. J. Phys., B10, 406, 1960.
ASSOCIATION: Institut poluprovodnikov AN USSR, Kiyev (Inatitute of Semi-
conductors, AS UkrSSR, Kiyev)
SUBMITTED: September 20, 1961
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S/181/62/OD4/008/001/041
B125/B104
AUTHOR$: Litovahenko, V. G., and Lyasheriko, V.
TITLE: Adhesion of non-equilibrium carriers on the surface of
germanium
PERIODICAL: Fizika tverdogo, tela, v. 4, no. 8, 1962v 1985-1993
TEXT: The temperature dependence of the relaxation of photoconductivity
of thin germanium specimens was investigated. The adhesion of minority
carriers was proved by the following results: (1) The filling of the traps
with carriers broduced by a constant light of high intensity e@:cludes the
recombination mechanism of the relaxation of photoconductivity at low
temperatures. (2)'The carriers produced by 1;he'pulse itself fill tho traps
completely. At 2000K the relaxation curve is exponential whe
n Yinj 's
small, but becomes lose exponential with inaveaeing y inj' (3) With weak
signals and low trap concentrations the mobile pairs responsible for photo-
conductivity are extracted from the specimen by a sufficiently strong
longitudinal electric field. In the presence of carriers adhering to the
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Adhesion of non-equilibrium carriers ... B125/B104
surface, the excited carriers near the adhesion center are looalized and
cannot be extracted. (4) If injection is achieved by a rectifying contact,
the relaxation of non-equilibiium conductivity has a long-wave component
at very small Yin j and low temperatures. This component is destroyed by
weak illumination. (5) If pairs are injected into well-developed inverse
or accumulation lay ers, long-lasting relaxation is observed at small Yi 1 1 4
n
and low temperatures. (6).Long-lasting relaxation occurs primarily in the
case of n-type conductivity. Further experiments indicate the occurrence of
carriers on the surface, and not inside the germanium specimen. Adhesion Of
carriers of one sign on the surface automatioally excludes carriers of the
other sign from carrier conduction in the interior, and the free carriera
will move only parallel to and in the vicinity of the surface. Adhesion
occurs at temperatures vhich are the higher the thinner the specimen. The
lifetime of free electrons*adhering to the surface is given by
UB) (2)
exp (El'
lnt, sITT, -sh UO f
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Adhesion of non-equilibrium carriers ... B125/B104
with illumination it is --an
-no
cxp (Ej I -Y. - UR)
F,
T., (C-VnO) f (3)
The notations are obviously taken*from W. Shockley, W. Read. Ph@a. Rev.,
87, 835, 1952. There are 4 figures.
ASSOCIATION:. Institut poluprovodnikov, AN USSR Kiyev (Instizute of
Semiconductors AS UkrSSR, Kiyev)
SUBKITTED. December 25, 1961
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44-2.5
8/181/62/004/01()/045/063
? B102/B112
AUTHORS: Primachenko, V. Ye., Litovchenko, V. G., Lyashenko, V. I.,
and Snitko, 0. V.
TITLE: Mino Aty carrier adhesion on.the silic*bn surface
PERIODICAL: Fizika tverdogo tela, v. 4, no. 10, 1962, 2925-2930
TEXT: This paper is aimed to show that under certain conditions a
charge accumulation may occur on the silicon surface and that the
bipolarity On - np) may be disturbed. This is, however, contradictory
to the observations made by other authors (see e.g. Phys.Rev.101, 1272,
1956; Semic.Surf.Pbys.,85,1957). The disturbance of bipolarity of the
intrinsic photoconductivity obsqrved is attrAuted to minority carriers
accumulating on fast surface lelels. The same method of investigation
was used as described in previous papers (FTT 9980,1959; FTT 2, 591,
1960;,UFZht59345,1960). The specimens were.n-type Si single crystal
platelets 200-40OP thick with resistivities of 30 - 200 ohm-om and volume
lifetimes of -41000peec, the surfaces of which had been etched with CP-8.
In germanium the bipolarity,c@f the surface photocurrent may be disturbed
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Minority carrier adhesion on
Only at low-temperatures, but. in etched silicon it may be disturbed even
at room temperature. This is proved (1) by the..nature of the photo-
conductivity relaxation of @hin samples if the oscillogram sho%s tso
exponents with widely differing time constants;.,(2).by the constant Tsh
of the short-term photocurrent component being 'inver3ely proportional
to the electric field appli6d@ whereas the constaht of the long-term
component is independent of It; (3) by the fact that the long-term
component can be caused to vanish by the usual method of trap filling;
(4) by the long-term component increasing as-the temperature decreases,
while the short-term component decreases and almost vanishes completely,
this being related to the intensified charge accumulation; in both cases
ln,r - f(I/T) follows a linear course; (5) by the results obtained in a
study of the kinetics of the field effect also in@dicating a disturbance
!of bipolarity. This bipolarity is L180 indicated by the field dependence
-r sh and -ri and (7) it is particularly pronounced in samples kept on
air for a longer period of time after they had been etched. (6) Experiments
on the condenser photo-emf proved that the disturbance of the photocurrent
bipolarity of Si is related to a change'.in the surface charge. Suoha
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Minority oarrier adhesion on B102/B112
disturbanoe occurs whe.. Cn Etv- v no 2.5 p) a nonmonotonic variation with
several maxima, a set of clearly pronounced "ledges" at medium wavelengtho and a

-ap"MmarIMIN
ACC NRs AF6oip-476
smooth rise in photoconductivity w:L. i decreasing wavelength to the absorprJon edge.
At low temperatures the spectra exhibited a more monotonic behavior. 7he presence
of Vae structure in the spectra indicates a discrete character of the energsr distri-
butiDn for the main surface traps. The activation energies calculated from the spec-
tra agreed with those obtained from the differential field effect. The dependence
of the infrared conductivity of the illumination, its kinetics, and the influence of
illumination with white light on the spectra and on the kinetics were also investi-
gateA. In the latter case it in possible to determine the surface potential without
kno,%ring the minimum of the surface conductivity. It is concluded that detailed in-
vestigations of the spectra of surface infrared conductivity and its kinetics as well
as its temperature and. field dependence, can serve as an effective new method of
investigating the properties of surface centers and the laws governing the non-
equilibrium processes which occur in the space-charge region. Orig. art. has;
6 figures and 3 formulAs.
SUB CODE: 20/ SUM DATE; OlSep65/ ORIG REF: 0151 OTH REF: 007

--L-06264-67 EWT(I)/EW'r-(m)/94P( t)/ET1
-ACC-N-'R
AP6030975
UP(e) JD
CODE: UR/0181/66/008/009 27 5 2767
SOURCE
AUTMORt Kovbawruko V. P.; Utovchenko, V. G.
ORG: Institute of Sevdcondilators, AN lft'@SR,_ KieL-(Institut poluprovodnikov AN
UkrSSR) 0(
TITIZ9 Effect of external electric field on the infrared Photoconduct of UEHei
silicon
SOURCE: Fizika tverdogo tela, v. 8, no. 9, 2765-2767
TOPIC TAGS1 photoconductivity, electric field, IR radiation
'LB'TRACT,
1 3 1 The article describes t effect of an external electric field on the IR
photoconductivity observed in thin@- 0.5 mm) samples of n- and p-type silicon con-
taining impurities in amounts less than 1o13 cm-3. This affect Is important in deter
m1aing the mechanisms of formation of extrinsic photoconductivity. The field E was
5 X 165 V/cm, and the photoconductivity was measured in the 0.9-3 p wavelength range
at 29711C. IR photoconductivity spectra obtained In the aInsence and presence of the
external field are compared with the spectrum of surface traps obtained from the dif-
forential field effect. It is shown that in most cases the photoactive absorption of
IR-light on surface centora is due to "impurity center - majority carrier band" tran-
sitions. Orig. art. has3 I figure and 2 formulas.
SM CODE: 20/ SUB14 DATE: 22Feb66/ ORIG REFS 007/ OTH REFS 001
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ACC NRi AP7002665 so /0076/008G;
AUTHOR: Litovehenko, V. G., Frolov, 0. S., Vengris, S. A., Serba, A. A.
A.
Sadovnichiy
Nt;
ORG: none
J. TITLE: Photoelectrfic characteristics of the capacitance of a surface charge varicap
"OURCE: Radiotekhnika i elektronika, v. 12, no. 1, 1967, 76-86
TOPIC TAGS: varactor diode, silicon semiconductor
ABSTRACT: The photoelectric properties of the spacecharge capacitance of metal- I
oxide-silicon (MOS) varicaps were studied. The varactors were made from rec-
langular high-resistance (5 x 101 - 5 x 102 ohms/cm) photosensitive
silicon chips (dimensions, 15 x 5 x 0. 5 mm). The varicap was made from one part
2
of the chip (area of -the semitransparent metallic electrode, '@,10-2_ 1 Mm ; thick-
ne ss of the oxide, It- 0. 3 4 ). The other part of the chip was used for photocon-
ductance measurements from which the level of injunction of electron-hole pairs
6n was calculated. The varicap was illuminated with a tungsten incande scent lamp; I
the intensity was varied with platinum filters. The capacitance of the samples was
Card 1/2 UDC: 621. 383. 5

Acd -f4 kfi76ad@,
measured with a resonance circuit in the 50-100-Me frequency range at different
bias voltages; the maximum amplitude of the measuring a-c signal applied to the
varactor was 25 mv. Two types of varactors were studied: 1) those with low
lateral resistance (the dielectric layer had Pok '-% 108 ohms/cm); 2) those with high
lateral resistance (Pok,;" 1011 ohms/cm). Capacitance was found to increase wif.1
increasing light intensity and to decrease with increasing reverse bias in both
cases. Capacitance was also found to decrease with increasing frequency in both
types of varactor. Orig. art. has: 10 figures and 3 formulas.
SUE CODE: 096f .SUBM DATE: 03A-Lig65 ORIG REF: 004 OTH Rr.,F: 007/

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