THE BELL SYSTEM 



TECHNICAL JOURNAL 



voLUMEXXxiii JULY 1954 number4 



Copyright, 1964, American Telephone and Telegraph Company 



Negative Resistance Arising from Transit 

 Time in Semiconductor Diodes 



By W. SHOCKLEY 



(Manuscript received January 22, 1954) 



The structural simplicity of two-terminal compared to three-terminal 

 devices indicates the potential importance of two terminal devices employing 

 semicondvctors and having negative resistance at frequencies properly re- 

 lated to the transit tiryie of carriers through them. Such negative resistances 

 may he combined with im symmetrically transmitting components, such as 

 gyrators or Hall effect plates, to form dissected amplifiers that may he made 

 to simulate conventional three-terminal amplifiers and operate at high fre- 

 quencies. The characteristics of several structures are analyzed on the hasis 

 of theory and it is found that negative resistances are possible for properly 

 designed structures. 



1. NEGATIVE RESISTANCE AND DISSECTED AMPLIFIERS 



Because the drift velocities of current carriers in semiconductors are 

 smaller than the velocities attainable in vacuum tubes, transistor struc- 

 tures must be smaller to achieve comparable frequencies. In principle 

 it is possible, of course, to make compositional structures (i.e., distribu- 

 tions of donors and acceptors) in semiconductor crystals on a scale much 

 smaller than is possible for vacuum tubes. At present, however, the 

 available techniques are limited and it may require many years before 

 the ultimate potentialities are approached. 



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