GERMANIUM TRANSISTOR DEVELOPMENT AT VEB WERK FUER BAULEMENTE DER NACHRICHTENTECHNIK, TELTOW

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00810A005700440007-7
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 2
• Document Creation Date: December 20, 2016
• Document Release Date: December 7, 2007
• Sequence Number: 7
• Publication Date: January 1, 1955
• Content Type: REPORT

Approved For Release 2007/12/07: CIA-RDP80-0081 OA005700440007-7
CLASSIFICATION. sUC:ZET
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DATE OF
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NO. OF ENCLS.
GUSTED BELOW!
SUPPLEMENT
REPORT NO.
THIS IS UNEVALUATED INFORMATION
1. Through application of the Bridgeman method for the making of pure
germanium monocrystals, DEB perk flier Baulemente der Nachriohtenteohnik,
Carl von Ossiotzky (formerly Dralowid), in Teltow, has succeeded in
producing crystals with a degree of purity of 40 ohm centimetersl. 25X1
Samples of point-contact transistors made from these crystals during
the development process have an output amplification up to 1,000, with
a voltage amplification amounting to several h-.ndred. During October
and November 1954, the Dralowid transistor development team under the
supervision of Dr. Mathias Falter, assisted by mathematicianG. Heaabas
and physicist Blankenburg (fnu), succeeded in further improving
the purity of the germanium monocrystals obtained through the applica-
tion of the Bridgeman method. The maximum degree of purity reached as25X1
of mid-November 1954 was 55 ohm centimeters.
2. Daring the fall of 1954, the Dralowid plant started to build an installs-
tion for the application of tho "zone melting procedure" (Zoneneehmele..
verfunren) for the purification of germanium. However, the Dralowid
development teair. ai.=,e?;sed in one important essential from this method.
The essential feature of this procedure cons-Lots of melting germanium
monocrystals gradually; the ^onocrystals are not contained in
crucibles during the process, to avoid the diffusion of impurities from
the walls of the crucible into the germanium. The Dralowid plant, how-
ever, used a quartz container called a Sohiffohen , shaped lilos halt
of l,n oblong half tube (i.e. a tube halve a ong its longitudinal axis).
The germanium was pulp into this half tube and the h ff 3sa,' with its
germanium contents was placed in a larger quartz tube. is quartz
tube was surrouaidby induction coils of .two windings each; the coils
were at intervals of IQ centimeters from each other. There were four
or five coils. The coils were heated by a transmitter and the quartz
tube with the ASM&ink inside it uas moved horizontally at a slow
speed within the coils. n this way, the germanium was melted and
purified. It develoaed that the purified germanium still contained
too many silicon impurities i --' from the quartz, because the
silicon impurity ratio (the number of impurities in crystallized germa+-
mi.um in relation to their number in molten germanium), is greater than 1,
As soon as this mistake was realized, the Dralowid team decided to apoly
the "one melting procedure in its original version. In this version,
CLASSIFICATION SF~I~T
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 Approved For Release 2007/12/07: CIA-RDP80-00810A005700440007-7
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the germanium is spoved thro' gh mtlfiing ;ones without being 'pat into a
cont:-.iner9 and thus without being- exposed to contaar,,Er iia^u.rities._ This
imprpsd version of the ::ona melting prooec'.~ r h or;ever9 had not,
been net started, because the transmitter fo: icicuction'heating
bUke down in. early November. 1"11""4 and v,r s uriri rg:ir.` repairs,,
3 The Dralowid team also co,rplete 1 an nstallsu':;ier, 'dr ~h.e ap7licn-
t .on of the Czrochalst;y thod~ fcr the Purr.` Ica , .^n of germana:_:m
The first results cbtai.nnd were germanium, o.-: i0 centz
meter length with a (iiarieter of 5 millimeters. hose 7:r"?stuls, )io :ever,.
did not have straight shapes but ware rather uneven it 4.1:'rie,.e:~s Oz.,e to
bar temperature control d 1d not exceed the
degree of purity of the best s:-ir.:)le:3 obtained tough the applicat.on
of Ibe i$f: an.~etkiac~ ,;4e experi:rtents tvs.t:; h C^rochalsF;y i .r 11
ation~ tpn,?Pe q9* nu as soon the tr,. smitter for induction;
nz was as repaired. It is rppx?ti- that
her.tin?(a 3.5 krxb
t rou' R, ?t~t?rro the esent Orrochalsky instal l at-* .,n more hoz,o -
gefious crystals can be obt: in ,1 than through ann':ica 4ion of the tr .cigge
man ._;ethodo The hiChect purity oht- fined with the Bridgeman methcd is
`: found well in,dt3'e the ger.:,aniu ot. er
la.Yers ~iave varying de?,rei2s of i tnuri c~ .
4. rc uctioa of )tint- oonvaCt germanium transist r.:i rin.,i to be star ter In
e r1 1a' The Drz:I owic? l s t had received nositive aesu -enee f r .. ;e
State i'1a_inin? e eceS .iry und.., iiiO1iId be ra: de ^Vz:j'_
~able,
:'.o essential progress had been mode as yet b;yl 4 ;~'~eres team -Ili tj_
develo men.t of junction.-ty,,e germanium transistor.., The plan for this
development provided that it should be com,plci ec by the end of i 9 r;
Approved For Release 2007/12/07: CIA-RDP80-00810A005700440007-7