Low-Cost Deep Trench Decoupling Capacitor Device and Process of Manufacture

A decoupling capacitor (decap) structure formed in a semiconductor substrate having a trench insulator structure formed therein, said decap comprising:

• a capacitor trench formed in said trench insulator structure, said trench of less width than a width of said trench insulator structure and extending into said substrate, said trench having a capacitor dielectric layer lining the sidewalls and bottom of said trench;
• an inner decap electrode formed of a doped semiconductor material deposited in said capacitor trench;
• an outer decap electrode comprising doped semiconductor material regions formed adjacent said trench beneath said trench insulator structure in said substrate;
• and,
• an outdiffuse plate comprising a doped semiconductor material formed adjacent said capacitor dielectric layer lining and connecting with said outer decap electrode beneath remaining portions of said trench insulator structure.

A method of forming a decoupling capacitor (decap) in a semiconductor substrate comprising:

• a) forming a capacitor trench in a trench insulator structure, said trench of less width than a width of said trench insulator structure and extending into said substrate below said trench insulator structure;
• b) forming a capacitor dielectric layer to line sidewalls and bottom of said capacitor trench;
• c) filling said lined capacitor trench with a doped semiconductor material to form an inner decap electrode;
• and,
• d) forming doped semiconductor material regions adjacent said capacitor trench beneath said trench insulator structure in said substrate, said doped semiconductor regions forming an outer decap electrode and is of a same doping type as said doped semiconductor material inner decap electrode.

A decoupling capacitor (decap) structure formed in a semiconductor substrate having a buried insulator layer beneath a surface of said substrate, said decap comprising:

• a capacitor trench extending beneath said buried dielectric layer and extending into said substrate;
• a capacitor dielectric layer lining the sidewalls and bottom of said trench;
• an inner decap electrode formed of a doped semiconductor material deposited in said capacitor trench;
• and,
• an outer decap electrode comprising doped semiconductor material regions formed adjacent said trench beneath said trench insulator structure in said substrate.

A method of forming a decoupling capacitor (decap) in a semiconductor substrate having a buried insulator layer formed therein, said method steps comprising:

• a) forming a capacitor trench in said substrate that extends into said substrate below said buried insulator layer;
• b) forming a capacitor dielectric layer to line sidewalls and bottom of said capacitor trench;
• c) filling said lined capacitor trench with a doped semiconductor material to form an inner decap electrode;
• and,
• d) forming doped semiconductor material regions adjacent said capacitor trench beneath said buried insulator layer in said substrate, said doped semiconductor regions forming an outer decap electrode and is of a same doping type as said doped semiconductor material inner decap electrode.

A method of forming a decoupling capacitor (decap) structure in a semiconductor substrate comprising:

• a) forming a first trench of a width and depth in said substrate;
• b) forming a second trench in said substrate at a location of said first trench, said second trench of a width wider than said width of said first trench, wherein forming of said second trench extends the depth of said first trench into said substrate below said second trench;
• c) depositing insulator material in said first and second trenches and removing insulator material in said extended first trench and in a portion of said second trench to form a said decap trench;
• d) forming a capacitor dielectric layer to line sidewalls and bottom of said decap trench;
• e) filling said lined capacitor trench with a doped semiconductor material to form an inner decap electrode;
• and,
• f) forming doped semiconductor material regions adjacent said decap trench in said substrate, said doped semiconductor regions forming an outer decap electrode.