Method of forming atomic force microscope tips

A method of forming silicon atomic force microscope tips including the steps of:

• (a) depositing a masking layer onto a first layer of doped silicon so that some square or rectangular areas of the first layer of doped silicon are not covered by the masking layer,
• (b) etching pyramidal apertures in the first layer of doped silicon,
• (c) removing the masking layer,
• (d) depositing a second layer of doped silicon onto the first layer of doped silicon, the second layer of doped silicon being oppositely doped to the first layer of doped silicon,
• (e) etching away the first layer of doped silicon,
• (f) before the first layer of doped silicon is etched in step (e) performing an anisotropic wet etch on the second layer of silicon to provide at least one raised area,
• (g) fusion bonding a third layer of silicon over the raised area to form at least one cavity between the second layer and the third layer,
• (h) following the step of etching away the first layer of doped silicon in step (e)
• depositing a second masking layer over the second layer of silicon on the side previously in contact with the first layer of silicon,
• (i) patterning the second masking layer to include an area of no masking at one side of a tip,
• (j) performing a release etch to remove silicon above the cavity not covered by the second masking layer, and
• (k) removing the second masking layer, wherein the etch in step (e) is and electrochemical etch.

A method of forming silicon atomic force microscope tips including the steps of:

• (a) depositing a masking layer onto a first layer of doped silicon so that some square or rectangular areas of the first layer of doped silicon are not covered by the masking layer,
• (b) etching pyramidal apertures in the first layer of doped silicon,
• (c) removing the masking layer,
• (d) depositing a second layer of doped silicon onto the first layer of doped silicon, the second layer of doped silicon being oppositely doped to the first layer of doped silicon,
• (e) etching away the first layer of doped silicon,
• (f) before the first layer of doped silicon is etched in step (e) performing an anisotropic wet etch on the second layer of silicon to provide at least one raised area,
• (g) fusion bonding a third layer of silicon over the raised area to form at least one cavity between the second layer and the third layer,
• (h) following the step of etching away the first layer of doped silicon in step (e)
• depositing a second masking layer over the second layer of silicon on the side previously in contact with the first layer of silicon,
• (i) patterning the second masking layer to include an area of no masking at one side of a tip,
• (j) performing a release etch to remove silicon above the cavity not covered by the second masking layer, and
• (k) removing the second masking layer, wherein the first layer of silicon is p-type doped silicon and the second layer of silicon is n-type doped silicon.