Nitride cantilevers with single crystal silicon tips

US5066358A · kind A · utility

Assignee

• Board of Trustees of the Leland Stanford Junior University · US

Inventors

• Calvin F. Quate · Stanford, US
• Marco Tortonese · Mountain View, US

Key dates

• Filing date: Oct 27, 1988
• Grant date: Nov 19, 1991
• Expiry date: Oct 27, 2008

Classification

• Technology area (CPC G): Physics
• CPC primary: G01Q70/14
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A nitride cantilever is formed with an integral conical silicon tip at the free end thereof. A top layer of silicon dioxide is patterned into a tip mask on a doped or epitaxial silicon layer in a silicon substrate. Photoresist is spun on the silicon substrate and patterned and the silicon is etched to define a cantilever pattern in the substrate with the tip mask positioned to be near the free end of a nitride cantilever to be subsequently formed. A bottom layer of silicon dioxide is formed on the silicon substrate and then patterned and etched to define a masking aperture on the bottom silicon dioxide layer. The bottom of the silicon substrate is anisotropically etched through the masking aperture and the etch stops at the doped silicon layer. Alternatively, electrochemical etching is done by applying an electric potential across the P-N junction between the doped silicon layer and the appropriately-doped substrate. This releases the free end of the doped silicon layer from the silicon substrate. The anisotropic etch preferentially etches all of the crystal planes of the silicon substrate except the (111) planes to leave a silicon base from which extends the silicon surface layer …