Fabrication of Single Crystal Silicon Nanosurfaces A. Sprunt & A. Slocum Fracture fabrication of planar surface pairs with nanometer scale roughness or perfect complementarity whose separation can be precisely controlled. Fabrication of an electrostatically actuated variable parallel plate capacitor with fractured silicon surfaces for electrodes. Fabrication of parallel nanosurface pairs by anisotropic etching of (110) silicon wafers and the surrounding structure necessary to precisely control the separation of those surfaces. CBA 2004 Site Visit - June 10

Two-Stage Device KOH-align and notch Experimented with different specimen orientations, specimen thicknesses, and notching techniques. CBA 2004 Site Visit - June 10

Fracture Surfaces CBA 2004 Site Visit - June 10 1) Completed experiments on differnt types of specimen notching techniques. Notching across the full width of the specimen with KOH produces the best surfaces. For images, see "knowledge nugget" and accompanying slides. 2) Determined that thinner specimens produce superior surface finish. By using a thinner specimen, the portion of the fracture surface produced when the crack is moving unacceptably quickly is effectively removed. Again, see "knowledge nugget" and accompanying slides for images. 3) Fractured specimens oriented on both the (110) and (100) crystal planes and determined the (110) specimens are superior. CBA 2004 Site Visit - June 10

Variable Capacitor CBA 2004 Site Visit - June 10

Predicted Performance & Fabrication Native oxide thickness: 4 nm Minimum stable gap: 4 nm Capacitor Voltage: 1 V Native Oxide Thickness Composite micrograph of process development device released in air. CBA 2004 Site Visit - June 10

Timeline Fractured flexure only at specimen Sept 2002 FIB notching experiments Oct 2002 Two-Stage Device March 2003 KOH notching experiments Nov 2003 First Variable Capacitor Devices July 2004 CBA 2004 Site Visit - June 10