US 5,706,163 A · ESD-protected thin film capacitor structures

Abstract

A thin film protected capacitor structure having a thin film capacitor and a protection device is provided on an integrated circuit wafer. The wafer has a low resistivity substrate of a first type disposed under an epitaxial layer of a second type different from the first type. The structure includes a first heavily doped region, which is of the first type, in and through the epitaxial layer, and an oxide layer having a first oxide region disposed above the first heavily doped region. The first heavily doped region and the low resistivity substrate form the first plate of the thin film capacitor. There is also included a metal layer disposed above the first oxide region. A portion of this metal layer forms the second plate of the thin film capacitor. Between the second plate and the first plate, the aforementioned first oxide region represents the insulating dielectric. There is also included a second heavily doped region in the epitaxial layer. This second heavily doped region, being of the first type and in electrical contact with the metal layer, has a thickness that is less than the thickness of the epitaxial layer. The protection device is formed from this second heavily doped region, the epitaxial layer, and the low resistivity substrate.

Claims26

Dependent claims

A thin film protected capacitor structure having a thin film capacitor and a protection device, said thin film protected capacitor structure being fabricated on an integrated circuit wafer, said wafer having a low resistivity substrate disposed under an epitaxial layer, said low resistivity substrate being of a first type and said epitaxial layer being of a second type different from said first type, comprising:

a first heavily doped region in and through said epitaxial layer, said first heavily doped region being of said first type;
an oxide layer having a first oxide region disposed above said first heavily doped region, said first heavily doped region being in electrical contact with both said first oxide region and said low resistivity substrate to form a conducting path between an underside of said first oxide region and said low resistivity substrate through said epitaxial layer, whereby said first heavily doped region and said low resistivity substrate represent a first plate of said thin film capacitor;
a metal layer disposed above said first oxide region, a portion of said metal layer forming a second plate of said thin film capacitor, whereby said first oxide region representing an insulating dielectric between said first plate and said second plate;
and
a second heavily doped region formed in said epitaxial layer, said second heavily doped region having a thickness that is less than the thickness of said epitaxial layer, said second heavily doped region being of said first type and in electrical contact with said metal layer, whereby said second heavily doped region, said epitaxial layer, and said low resistivity substrate form said protection device.

2 more elements

A method for fabricating an integrated circuit having therein a thin film protected capacitor structure on a wafer, said wafer having an epitaxial layer disposed above a low resistivity substrate, said low resistivity substrate being of a first type and said epitaxial layer being of a second type different from said first type, comprising:

implanting dopants of said first type into a first region of said epitaxial layer, thereby forming a first heavily doped region in and through said epitaxial layer, said first heavily doped region being of said first type and in electrical contact with said low resistivity substrate;
forming an oxide layer, said oxide layer having a first oxide region disposed above said first heavily doped region;
and
forming a metal layer, said metal layer having a first metal region disposed above said first oxide region, whereby said first metal region representing a first plate of a thin film capacitor of said thin film protected capacitor structure, said first oxide region representing an insulating dielectric layer of said thin film capacitor, and both said first heavily doped region and said low resistivity substrate representing a second plate of said thin film capacitor.

1 more element

Dependencies are inferred from the claim text.

ESD-protected thin film capacitor structures

Life of this patent

ESD-protected thin film capacitor structures

Life of this patent

Abstract

Claims26