Isolated diode

• US 20080197446A1
• Filed: 02/27/2008
• Published: 08/21/2008
• Est. Priority Date: 08/14/2002
• Status: Active Grant

• Current Assignee: Advanced Analogic Technologies Incorporated (Skyworks Solutions Incorporated)
• Original Assignee: Advanced Analogic Technologies Incorporated (Skyworks Solutions Incorporated)
• Inventors: Williams, Richard K., Disney, Donald R.
• Granted Patent: US 7,834,421 B2
• Time in Patent Office: Days
• US Class Current: 257/506
• CPC Class Codes: H01L 21/761 PN junctions
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264
• CPC Class Codes: H01L 21/763 Polycrystalline semiconductor regions H01L21/76264 takes precedence
• CPC Class Codes: H01L 21/765 by field effect H01L21/76264 takes precedence
• CPC Class Codes: H01L 27/0629 in combination with diodes, or resistors, or capacitors
• CPC Class Codes: H01L 27/0802 Resistors only
• CPC Class Codes: H01L 29/861 Diodes

Abstract

Various integrated circuit devices, in particular a diode, are formed inside an isolation structure which includes a floor isolation region and a trench extending from the surface of the substrate to the floor isolation region. The trench may be filled with a dielectric material or may have a conductive material in a central portion with a dielectric layer lining the walls of the trench. Various techniques for terminating the isolation structure by extending the floor isolation region beyond the trench, using a guard ring, and a forming a drift region are described.

Claims

1. An isolated diode formed in a semiconductor substrate of a first conductivity type, the substrate not comprising an epitaxial layer, the isolated diode comprising:

a floor isolation region of a second conductivity type opposite to the first conductivity type submerged in the substrate;

a trench extending from a surface of the substrate at least to the floor isolation region, the trench having a central portion filled with a conductive material and a dielectric material lining the walls of the trench, the conductive material providing electrical contact from the floor isolation region to the surface of the substrate, the trench and the floor isolation region together forming an isolated pocket of the substrate; and

an anode region of the first conductivity type in the isolated pocket, the anode region extending from the surface of the substrate to the floor isolation region.

2. The isolated diode of claim 1 comprising:

a dielectric layer above the surface of the substrate, the dielectric layer having a first opening above the anode region and a second opening above the conductive material;

an anode contact in the first opening in contact with the anode region; and

a cathode contact in the second opening in contact with the conductive material.

3. The isolated diode of claim 1 wherein the anode region comprises a shallow portion and a deep portion, the shallow portion being located adjacent the surface of the substrate, the deep portion being located below the shallow portion, the shallow portion having a first doping concentration, the deep portion having a second doping concentration, the second doping concentration being greater than the first doping concentration.