Junction barrier schottky diode having high reverse blocking voltage
View Patent ↗A junction barrier Schottky diode has an N-type well having surface and a first impurity concentration; a p-type anode region in the surface of the well, and having a second impurity concentration; and an N-type cathode region in the surface of the well and horizontally abutting the anode region, and having a third impurity concentration. A first N-type region vertically abuts the anode and cathode regions, and has a fourth impurity concentration. An ohmic contact is made to the anode and a Schottky contact is made to the cathode. The fourth impurity concentration is less than the first, second and third impurity concentrations.
1. A junction barrier Schottky diode in an integrated circuit, the diode comprising:
an N-type well having a surface and a maximum first impurity concentration at the surface in a P-type substrate;
a P-type anode region in the surface of the well and having a bottom surface, and having a second impurity concentration;
an N-type cathode region in the surface of the well adjacent the anode region and having a bottom surface, and having a third impurity concentration;
a first N-type region vertically abutting the bottom surfaces of the anode and cathode regions, and having a fourth impurity concentration at the bottom surface of the anode region;
a buried N-type region in the N-type well and having a fifth impurity concentration;
an ohmic contact to the anode region, a Schottky contact to the cathode region and an ohmic contact to the buried region from the surface; and
the fourth impurity concentration at the bottom surface of the anode region being less than the maximum first, second, third and fifth impurity concentrations.
2. The diode of claim 1 , wherein cathode and anode regions have substantially the same depth.
3. The diode of claim 1 , wherein cathode and anode regions are concentric.
4. The diode of claim 1 , including two spaced anode regions and the cathode region is between the two spaced anode regions.
5. The diode of claim 4 , wherein the space between the two anode regions is less than 1 micron and is selected for a specific forward voltage drop and leakage current.
6. The diode of claim 1 , including two spaced cathode regions and the anode region is between the two spaced cathode regions.
7. The diode of claim 6 , wherein the space between the two cathodes regions is less than 1 micron and is selected for a specific forward voltage drop and leakage current.
8. The diode of claim 1 , wherein a maximum impurity concentration of the anode region is below the surface.
9. The diode of claim 1 , wherein the fourth impurity concentration is at least one order of magnitude less than the second impurity concentration's maximum, and the fourth impurity concentration is at least one order of magnitude less than the third impurity concentration's maximum.
10. The diode of claim 1 , wherein the second, third and fourth impurity concentrations are of a value to produce a diode having a reverse blocking voltage of at least 60 volts.
11. The diode of claim 1 , wherein the first N-type region vertically separates the anode and cathode regions from the N-type well.