A semiconductor structure including a trench formed in a substrate and a buried isolation collar that extends about sidewalls of the trench. The buried isolation collar is constituted by an insulator formed from a buried porous region of substrate material. The porous region is formed from a buried doped region defined using masking and ion implantation or by masking the trench sidewalls and using dopant diffusion. Advantageously, the porous region is transformed to an oxide insulator by an oxidation process. The semiconductor structure may be a storage capacitor of a memory cell further having a buried plate about the trench and a capacitor node inside the trench that is separated from the buried plate by a node dielectric formed on the trench sidewalls.

Title
Methods for forming semiconductor structures with buried isolation collars and semiconductor structures formed by these methods
Application Number
11/262128
Publication Number
20070099391
Application Date
October 28, 2005
Publication Date
May 3, 2007
Inventor
Jack Allan Mandelman
Flat Rock
NC, US
Kangguo Cheng
Beacon
NY, US
Agent
IBM Corporation Dept 917
MN, US
Agent
James R Nock
MN, US
Assignee
International Business Machines Corporation
NY, US
IPC
H01L 21/76
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