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Browse Prior Art Database

Metal Oxide Semiconductor Capacitor

IP.com Disclosure Number: IPCOM000082256D
Original Publication Date: 1974-Nov-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 60K

Publishing Venue

IBM

Related People

Arzubi, LM: AUTHOR [+2]

Abstract

The capacitance per unit area of semiconductor surface can be increased by contacting a given layer of metal 10, such as aluminum, to a diffused region 12 in the semiconductor surface, and interposing another layer of metal 14 between the diffused region 12 and the metal layer 10.

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Metal Oxide Semiconductor Capacitor

The capacitance per unit area of semiconductor surface can be increased by contacting a given layer of metal 10, such as aluminum, to a diffused region 12 in the semiconductor surface, and interposing another layer of metal 14 between the diffused region 12 and the metal layer 10.

As shown in Fig. 1, a metal-oxide semiconductor (MOS) capacitor is formed by diffused region 12 in semiconductor layer 16, which is preferably made of silicon, and metal layer 14 with a first dielectric layer 18 interposed between region 12 and metal layer 14. The capacitance over diffused region 12 is increased to nearly double the capacitance produced by region 12 and layers 14 and 18, by providing metal layer 10 in contact with diffused region 12 and second dielectric layer 20 interposed between metal layers 10 and 14.

Preferably, metal layers 10 and 14 are aluminum, first dielectric 18 is silicon dioxide and second dielectric layer 20 is quartz, nitride or low-temperature pyrolytic silicon dioxide. With this structure, the capacitance from aluminum layer 10 to aluminum layer 14 is added to that from aluminum layer 14 to diffusion or diffused region 12. This structure is particularly useful when thick insulators or oxides must be employed on semiconductor layers or substrates and a large capacitance is desired.

In Fig. 2, a structure is illustrated wherein the capacitance per unit area of semiconductor surface is further increased, by depositing a...