How To Make a P-N-P-N Semiconductor Device

50 years ago this year, in its 'Patent Pointers' section, the Electronics Weekly edition of September 14th 1980 carried the following snippet.

'An ingenious way of making a P-N-P-N or an N-P-N-P semiconductor device which avoids the difficulty of the heat treatment of the second junction adversely affecting the first formed junction is described in Patent No. 844970, filed by British Thomson-Houston Co.'

The note continues:
'What is done is to form a first P-N junction by alloying semiconductor germanium of N type with semiconductor silicon of P type, the second junction being subsequently made by fusing indium to the germanium.'

The note ends:
'The second junction is made at a lower temperature than the first so that the first junction is unharmed.'

Posted by David Manners on August 17, 2010; TrackBack URL for this entry:
http://www.electronicsweekly.com/cgi-bin/mt/mt-tb.cgi/162252