Masking process for fabricating ultra-high aspect ratio, wafer-free micro-opto-electromechanical structures

A masking process for the fabrication of submicron, single-crystal released structures, comprising:

• oxidizing an exposed top surface of a wafer from which a single-crystal structure is to be fabricated;
• forming a first mask having a desired pattern on said wafer;
• forming an intermediate structure in said wafer by transferring said pattern into said wafer;
• transforming said intermediate structure into a second mask defined by said pattern;
• forming said single crystal structure by transferring said pattern into said wafer;
• and,
• releasing said single crystal structure from said wafer.

A masking process for the fabrication of submicron, single-crystal released structures, comprising:

• ion implanting a wafer;
• annealing said wafer in a high temperature furnace;
• oxidizing a top surface of said wafer with thermal silicon dioxide;
• depositing a LPCVD silicon dioxide mask material on said oxidized top surface;
• photolithographically forming a pattern in resist on said mask material;
• transferring said pattern to said mask material by ion etching;
• transferring said pattern into said wafer by ion etching into said wafer;
• oxidizing exposed wafer surfaces with thermal silicon dioxide;
• etching said oxidized surfaces leaving formed, patterned intermediate structures in said wafer;
• oxidizing exposed surfaces of said wafer with thermal silicon dioxide, including completely oxidizing said intermediate structures;
• removing said oxidized surface from said top of said wafer by ion etching, resulting in a second mask formed from said oxidized intermediate structures;
• transferring said pattern into said wafer by etching into said wafer;
• oxidizing exposed wafer surfaces with thermal silicon dioxide;
• removing said oxidized wafer surface from said top surface of said wafer;
• and,
• releasing said single crystal structure from said wafer using ion etching to completely undercut said single crystal structure.

A process for the fabrication of submicron, ultra-high aspect ratio structures, comprising the steps of:

• oxidizing an exposed top surface of a wafer;
• forming a first mask having a desired pattern on said wafer;
• forming an intermediate structure in said wafer by transferring said pattern into said wafer;
• and,
• transforming said intermediate structure into a second mask defined by said pattern.