Precision zener diodes and methods of manufacturing precision zener diodes

A Zener diode having an anode and a cathode, the diode packaged within an insulating package, the diode having conductive leads electrically coupled to the anode and to the cathode respectively, the diode comprising:

• a semiconductor base layer of a base layer conductivity type and of a base layer resistivity;
• a surface layer grown on the base layer, the surface layer having a surface layer conductivity type the same as the base layer conductivity type, the surface layer having a surface layer resistivity greater than the base layer resistivity, the surface layer in contact with the base layer and having an exterior surface opposite to the base layer;
• an internal region of semiconductor material having an internal region conductivity type consistent with the base layer conductivity type, the internal region extending through the surface layer and into the base layer;
• and
• a contact layer of a contact conductivity type opposite to the base layer conductivity type implanted at the exterior surface, the contact layer completing a central semiconductor junction with the internal region and the contact layer completing an edge semiconductor junction with edge portions of the base layer.

A consumer electronic product comprising:

• a housing operable to enclose and to protect electronics internal to the product;
• a user interface;
• and
• electrical circuitry operable to provide electrical signals to the user interface, the electrical circuitry including a Zener diode comprising:
• a semiconductor substrate layer of a substrate conductivity type and of a substrate resistivity;
• an epitaxial layer grown on the substrate layer, the epitaxial layer having an epitaxial layer conductivity type consistent with the substrate conductivity type, the epitaxial layer having an epitaxial layer resistivity greater than the substrate resistivity, the epitaxial layer having an epitaxial surface opposing the substrate layer;
• an interior region of doped semiconductor material having an interior conductivity type consistent with the substrate conductivity type, the interior region extending through the epitaxial layer and into the substrate layer;
• and
• a junction layer of a junction conductivity type different from the substrate conductivity type formed in the epitaxial surface, the junction layer forming an interior P/N junction with the interior region and the junction layer forming a peripheral P/N junction with a peripheral portion of the device.

A method of manufacturing a semiconductor device, the method comprising:

• depositing an epitaxial layer on a semiconductor substrate, the substrate doped with material of a substrate dopant type, the substrate having a substrate resistivity;
• implanting interior dopant ions of an interior region dopant type consistent with the substrate dopant type, the interior dopant ions entering the crystal structure of the epitaxial layer and the substrate forming an interior region extending through the epitaxial layer and into the substrate;
• and
• implanting junction dopant ions of a junction dopant type different from the substrate dopant type the junction dopant ions entering a crystal structure of the epitaxial layer and forming a junction layer, the junction layer forming an interior P/N junction with the interior region and the junction layer forming a peripheral P/N junction with a peripheral portion of the device.