Lateral passive device having dual annular electrodes
View Patent ↗A lateral passive device is disclosed including a dual annular electrode. The annular electrodes form an anode and a cathode. The annular electrodes allow anode and cathode series resistances to be optimized to the lowest values at a fixed device area. In addition, the parasitic capacitance to a bottom plate (substrate) is greatly reduced. In one embodiment, a device includes a first annular electrode surrounding a second annular electrode formed on a substrate, and the second annular electrode surrounds an insulator region. A related method is also disclosed.
1. A lateral passive device formed on a substrate, the lateral passive device comprising:
a first annular electrode surrounding a second annular electrode, and the second annular electrode surrounding a first annular insulator region, wherein the first annular insulator region includes a deep trench isolation through a shallow trench isolation, wherein the deep trench isolation through the shallow trench isolation is pillar-shaped and has a width that continuously tapers from one end below the shallow trench isolation to an end opposite therefrom, wherein the first annular electrode is doped with an n+ dopant to form a cathode in the lateral passive device, wherein the n+ dopant comprises one of phosphorous (P), arsenic (As) or antimony (Sb), and the second annular electrode is doped with a p+ dopant to form an anode in the lateral passive device, wherein the p+ dopant comprises one of boron (B), indium (In) or gallium (Ga); a second insulator region between the first annular electrode and the second annular electrode, wherein the second insulator region is annular and includes a shallow trench isolation; and a third annular insulator region surrounding the first annular electrode, wherein the third annular insulator region includes a deep trench isolation, wherein the pillar shape of the deep trench isolation through the shallow trench isolation is substantially circular, and wherein the deep trench isolation through the shallow trench isolation is discontinuous with the deep trench isolation of the third annular insulator region, wherein the second annular electrode has a bottom surface that is higher than a bottom surface of the second insulator region, wherein the bottom surface of the second insulator region is higher than a bottom surface of the first annular electrode.
2. The device of claim 1 , wherein the second insulator region has a width of no smaller than approximately 0.1 μm.
3. The device of claim 1 , wherein the lateral passive device is one of a lateral PN diode, a lateral PIN diode, a Schottky barrier diode or a varactor.
4. The device of claim 1 , wherein the first and second electrodes have a shape that is one of: substantially rectangular, substantially octagonal or substantially circular.