GB1126663A - Improvements in or relating to semiconductor devices and circuits - Google Patents

Abstract

1,126,663. Semi-conductor circuits. STANDARD TELEPHONES & CABLES Ltd. 9 Dec., 1965 [16 Dec., 1964], No. 51167/64. Heading H3T. [Also in Division H1] A circuit includes a body of semi-conductor material 10, of the type exhibiting the property that when it is subjected to a steady electric field exceeding a critical value, the resultant current flow contains an oscillatory component of frequency determined by the transit time of space charge instabilities through the material (e.g. the GUNN effect); a current source 12 producing a steady electric field between contacts 11 less than the critical value; and an input signal circuit which, in response to an input signal, raises the electric field above the critical value for a time shorter than the transit time to cause the current through the material 10 to undergo a single excursion from its steady value. The material may be a III-V- type semi-conductor, e.g. n-type gallium arsenide or indium phosphide. Fig. 2 (not shown) depicts a modification in which the input signal is fed to a third electrode insulated from the material adjacent a constricted part of the material between contacts 11, variation in the potential of this electrode controlling the depth of an associated depletion layer and therefore the local electric field. The current source 12 may be pulsed to reduce power dissipation in body 10. The circuit may be used as an amplifier and will handle variable frequency pulses or oscillatory signals, which may be frequency modulated. Fig. 1 shows a transmitter arrangement for a communications link, an input signal 15 modulating the frequency of oscillator 14.