Temperature compensated constant current source device

A temperature compensated semiconductor current source device having a first terminal which is adapted to be connected to an operating bias potential for producing a current at an output terminal thereof of which the magnitude is substantially independent to variations of the operating bias potential and temperature, comprising in combination:

• a junction field effect transistor having a predetermined, controlled pinch-off voltage characteristic and having;
• a. an epitaxial layer of semiconductor material of a first conductivity type;
• b. a drain electrode comprising a semiconductor material of a second conductivity type, said drain electrode being diffused into said epitaxial layer;
• c. a source electrode comprising said semiconductor material of said second conductivity type having a predetermined value of resistivity being diffused into said epitaxial layer;
• d. a source to drain channel region of said second conductivity type being formed into said epitaxial layer between said source and drain electrodes, said channel region being ion-implanted;
• e. a first region of a semiconductor material having a higher concentricity of said first type, said first region being diffused into said epitaxial layer adjacent to said source electrode;
• and
• f. a second region of said first conductivity type formed into said epitaxial layer which extends into said first region and having a bottom surface contiguous along the upper surface of said source to drain ion-implanted channel;
• g. first metal conductor means for connecting said first region to the first terminal of the device;
• h. second metal conductor means for connecting said drain electrode to the output terminal;
• said source electrode being extended in its physical area such that a linear diffused resistor is formed integrally therewith having a predetermined temperature coefficient that is a function of the resistivity of said semiconductor material comprising said source electrode;
• and
• said diffused resistor and said field effect transistor having respective temperature coefficients which compensate each other so that the magnitude of the current produced at the output terminal of the current source device is substantially independent to temperature variations.