Zener diode structure having three terminals

Claim 2

A zener diode fabricated in a monolithic integrated circuit structure and including in combination: a semiconductor substrate of a first conductivity type; a buried layer of a second conductivity type located in said semiconductor substrate; a layer of semiconductor material partly of said second conductivity type which covers and extends from said substrate and said buried layer, said layer of semiconductor material having an outwardly facing surface; a first portion of said layer of semiconductor material extending to said buried layer and being said first conductivity type of a given concentration; a second portion of said layer of semiconductor material extending from said surface of said layer of semiconductor material toward said substrate and surrounding said first portion, said second portion being said first conductivity type and having a concentration which is less than said given concentration, said second portion making conductive contact between said first portion and said outwardly facing surface; a third portion of said layer of semiconductor material extending from said surface and into said first portion to form a junction with said first portion, said third portion isolating said first portion from said outwardly facing surface of said layer of semiconductor material, said third portion being substantially surrounded by said second portion and of said second conductivity type, said third portion forming one of the anode and cathode elements of the zener diode, said first portion forming the other of said anode and said cathode elements of the zener diode; first conductive means located over said outwardly facing planar surface, said first conductive means having a contact making ohmic connection only to one region of said second portion; second conductive means located over said outwardly facing planar surface, said second conductive means having a contact making ohmic connection only to another regIon of said second portion; and third conductive means located over said outwardly facing planar surface, said third conductive means having a contact making ohmic connection only to said third portion.

Claim 3

The zener diode of claim 1 wherein said portions of said first conductivity type are P-type materials and said portions of said second conductivity type are N-type materials.

Claim 4

The zener diode of claim 1 wherein said first portion forms the anode and said third portion forms the cathode thereof.

Claim 5

The zener diode of claim 1 further including a fourth portion of said layer of semiconductor material extending from said surface of said layer of semiconductor material to said substrate, said fourth portion being of said first conductivity type and of said given concentration.

Claim 6

The zener diode of claim 1 wherein: said contact of said first conductive means is located closer to said contact of said third conductive means than is said contact of said second conductive means; said second conductive means and said third conductive means cooperating with said second semiconductor portion to facilitate energization of said junction located between said first semiconductor portion and said third semiconductor portion; and said first conductive means and said third conductive means cooperating with said second semiconductor portion to facilitate sensing of the voltage developed across said junction located between said first semiconductor portion and said third semiconductor portion.

Claim 7

A reference voltage supply circuit for providing a reference voltage of a constant magnitude between the terminals of a high impedance load, the reference voltage supply circuit including in combination: power supply means providing an output current between first and second output terminals thereof, said output current having an amplitude which tends to fluctuate; zener diode means formed in a layer of single crystal semiconductor material having a first portion with a first conductivity type of a given concentration, and a second portion extending from the surface of said single crystal material to said first portion having a second conductivity type, said first and second portions forming a junction beneath said surface of said single crystal material, and a third portion extending from said surface of said single crystal material and making conductive contact with said first portion, said third portion having a concentration of said first conductivity type which is less than said given concentration so that breakdown occurs across said junction; first means forming an ohmic contact to said third portion near a first boundary of said second portion; second means forming an ohmic contact to said second portion near said first boundary thereof; third means forming another ohmic contact to said third portion at another boundary of said second portion, said second and said third means being connected to said output terminals of said power supply means so that a breakdown voltage is developed across said junction; and said first and said second means being connected to said terminals of said high impedance load so that the reference voltage developed by said junction breakdown is applied to said terminals of said high impedance load.

Claim 8

A reference voltage supply circuit for providing a reference voltage of a constant magnitude between the terminals of a high impedance load, the reference voltage supply circuit including in combination: power supply means providing an output current between first and second output terminals thereof, said output current having an amplitude which tends to fluctuate; zener diode means formed in a layer of single crystal semiconductor material having a first portion with a first conductivity type of a given concentration, and a second portion extending from the surface of said single crystal material to said first portion having a second conductivity type, said first and second portions forming a junction beneath said surface of said single crystal material, and a third portion extending from said surface of said single crystal material and making conductive contact with said first portion, said third portion having a concentration of said first conductivity type which is less than said given concentration so that breakdown occurs across said junction; first means forming an ohmic contact to said third portion near a first boundary of said second portion; second means forming an ohmic contact to said second portion near said first boundary thereof; third means forming another ohmic contact to said third portion at another boundary of said second portion, said second and said third means being connected to said output terminals of said power supply means so that a breakdown voltage is developed across said junction; and said first and said second means being connected to said terminals of said high impedance load so that the reference voltage developed by said junction breakdown is applied to said terminals of said high impedance load.

Claim 9

The reference voltage supply circuit of claim 6 wherein said zener diode means, said first means, said second means and said third means are all included in a monolithic integrated circuit.

Claim 10

A zener diode having anode and cathode regions for use in a structure wherein electrical connections are made only through an outwardly facing planar surface and for providing a stable reference voltage, such zener diode including in combination: a layer of semiconductor material partly of a particular conductivity type havng the outwardly facing planar surface; a first semiconductor material of the other conductivity type located in said layer of semiconductor materiaL, said first semiconductor material having a deep portion and a shallow portion which are integral with each other, said deep portion forming one of the anode and cathode regions and extending a first distance from the outwardly facing planar surface into said layer of semiconductor material, said shallow portion forming a conductive path between said deep portion and the outwardly facing planar surface and extending a second distance from the outwardly facing planar surface into said layer of semiconductor material, said second distance being less than said first distance, said shallow portion having a lower impurity concentration than said deep portion; a second semiconductor material of said particular conductivity type extending between the outwardly facing planar surface and said deep portion and forming the other of the anode and cathode regions, said second semiconductor material and said deep portion of said first material cooperating to form a junction which is isolated from the outwardly facing planar surface; first conductive means having a first portion located on the outwardly facing planar surface and said first portion making electrical connection only to one region of said shallow portion; second conductive means having a second portion located on the outwardly facing planar surface and said second portion only making electrical connection to another region of said shallow portion; third conductive means having a third portion located on the outwardly facing planar surface and said third portion making electrical connection only to said second semiconductor material, said first and third conductive means facilitating energization of said junction; and said second and third conductive means facilitating sensing of the voltage developed across said junction.

Claim 11

A zener diode having anode and cathode regions for use in a structure wherein electrical connections are made only through an outwardly facing planar surface and for providing a stable reference voltage, such zener diode including in combination: a layer of semiconductor material partly of a particular conductivity type havng the outwardly facing planar surface; a first semiconductor material of the other conductivity type located in said layer of semiconductor materiaL, said first semiconductor material having a deep portion and a shallow portion which are integral with each other, said deep portion forming one of the anode and cathode regions and extending a first distance from the outwardly facing planar surface into said layer of semiconductor material, said shallow portion forming a conductive path between said deep portion and the outwardly facing planar surface and extending a second distance from the outwardly facing planar surface into said layer of semiconductor material, said second distance being less than said first distance, said shallow portion having a lower impurity concentration than said deep portion; a second semiconductor material of said particular conductivity type extending between the outwardly facing planar surface and said deep portion and forming the other of the anode and cathode regions, said second semiconductor material and said deep portion of said first material cooperating to form a junction which is isolated from the outwardly facing planar surface; first conductive means having a first portion located on the outwardly facing planar surface and said first portion making electrical connection only to one region of said shallow portion; second conductive means having a second portion located on the outwardly facing planar surface and said second portion only making electrical connection to another region of said shallow portion; third conductive means having a third portion located on the outwardly facing planar surface and said third portion making electrical connection only to said second semiconductor material, said first and third conductive means facilitating energization of said junction; and said second and third conductive means facilitating sensing of the voltage developed across said junction.

Claim 12

The zener diode of claim 8 wherein: said second semiconductor material is substantially enclosed by only said shallow portion of said first semiconductor material, the outwardly facing planar surface, and said deep portion; and said second semiconductor material being arranged to isolate said deep portion from the outwardly facing planar surface.

Claim 13

The zener diode of claim 7 wherein: said layer of semiconductor material and said second semiconductor material are of the N conductivity type; said deep portion of said first semiconductor material is of a P conductivity type of a given concentration; and said shallow portion is of a P conductivity type of a concentration which is less than said given concentration so that voltage breakdown first occurs between said deep portion of said material and said second material in response to a current applied through said second semiconductor material and said shallow portion.

Claim 14

The zener diode of claim 8 further including a semiconductor substrate of said other conductivity type forming a foundation for said layer of semiconductor material.

Claim 15

The zener diode of claim 11 further including: a buried layer of said particular conductivity type located in said semiconductor substrate and covered by said layer of semiconductor material; and said deep portion of said first material extending through said layer of semiconductor material to said buried layer, said buried layer electrically isolating said deep portion from said semiconductor substrate.

Claim 16

The zener diode of claim 8 wherein said first portion of said first conductive means is located closer to said third portion of said third conductive means than is said second portion of said second conductive means.