Method of making an integrated scanning tunneling microscope

• US 5,129,132 A
• Filed: 01/10/1990
• Issued: 07/14/1992
• Est. Priority Date: 01/27/1988
• Status: Expired due to Fees

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Albrecht, Thomas R., Zdeblick, Mark
• Primary Examiner(s): Hall, Carl E.
• Application Number:
  US07/463,108
• Time in Patent Office: 916 Days
• Field of Search: 29/25.35, 427/100, 310/310, 310/328, 310/332, 250/306, 250/307, 250/442.1, 156/643, 156/646, 156/651, 156/653, 156/657, 156/659.1, 156/662, 156/667, 437/194, 437/195
• US Class Current: 29/25.35
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: B82Y 35/00 Methods or apparatus for measurement or analysis of nanostructures
• CPC Class Codes: G01Q 10/045 Self-actuating probes, i.e. wherein the actuating means for driving are part of the probe itself, e.g. piezoelectric means on a cantilever probe
• CPC Class Codes: G01Q 60/16 Probes, their manufacture, or their related instrumentation, e.g. holders
• CPC Class Codes: G01Q 80/00 Applications, other than SPM, of scanning-probe techniques manufacture or treatment of nanostructures B82B3/00; recording or reproducing information using near-field interaction G11B9/12, G11B11/24, G11B13/08
• CPC Class Codes: G11B 9/14 using microscopic probe means , i.e. recording or reproducing by means directly associated with the tip of a microscopic electrical probe as used in Scanning Tunneling Microscopy [STM] or Atomic Force Microscopy [AFM] for inducing physical or electrical perturbations in a recording medium; Record carriers or media specially adapted for such transducing of information marking using electrical current B41M5/20; measuring roughness or irregularity of surfaces G01B7/34; details of scanning-probe microscopes G01Q
• CPC Class Codes: G11B 9/1418 Disposition or mounting of heads or record carriers G11B17/00 and G11B19/00 take precedence
• CPC Class Codes: G11B 9/1436 with provision for moving the heads or record carriers relatively to each other
• CPC Class Codes: G11B 9/1472 characterised by the form
• CPC Class Codes: H01J 37/20 Means for supporting or positioning the objects or the material; Means for adjusting diaphragms or lenses associated with the support introducing the objects H01J37/18
• CPC Class Codes: H10N 30/076 by vapour phase deposition
• CPC Class Codes: H10N 30/2046 adapted for multi-directional bending displacement
• CPC Class Codes: Y10S 977/837 Piezoelectric property of nanomaterial
• CPC Class Codes: Y10S 977/861 Scanning tunneling probe
• CPC Class Codes: Y10S 977/872 Positioner
• CPC Class Codes: Y10S 977/873 Tip holder
• CPC Class Codes: Y10S 977/943 Information storage or retrieval using nanostructure
• CPC Class Codes: Y10S 977/947 with scanning probe instrument
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

An integrated scanning tunneling microscope and an integrated piezoelectric transducer and methods for making both. The device consists of one or two arm piezoelectric bimorph cantilevers formed by micromachining using standard integrated circuit processing steps. These cantilevers are attached to the substrate at one area and are free to move under the influence of piezoelectric forces which are caused by the application of appropriate voltages generated by control circuitry and applied to pairs of electrodes formed as an integral part of the bimorph cantilever structure. The electric fields caused by the control voltages cause the piezoelectric bimorphs to move in any desired fashion within ranges determined by the design. The bimorph cantilevers have tips with very sharp points formed thereon which are moved by the action of the control circuit and the piezoelectric bimorphs so to stay within a very small distance of a conducting surface. The movements of the tip can be tracked to yield an image of the surface at atomic resolution.

Claims

1. A method of forming a piezoelectric motion transducer comprising:

forming a membrane in a substrate by etching a pit in a first surface of said substrate;

forming by any suitable microfabrication techniques a piezoelectric bimorph having first and second ends, said bimorph formed on a surface of a substrate opposite said first surface, said bimorph comprising first and second thin film piezoelectric layers sandwiched between a plurality of thin film conductors arranged relative to said thin piezoelectric films such that, when said bimorph has said second end freed from said substrate, three dimensional motion can be imparted to said second end by application of suitable voltage differences between pairs of said electrodes, said second end being formed over said membrane; and

freeing said second end of said bimorph from said substrate by etching through said membrane to leave said first end of said bimorph integrally attached to said substrate and thereby leaving said second end of said bimorph cantilevered in free space,

wherein said step of forming said bimorph comprises the steps of forming said first and second layers of piezoelectric material with zinc oxide or lead zirconate titanate sandwiched between said plurality of aluminum thin film conductors.

2. The method of claim 1 wherein the step of forming said bimorph includes the steps of forming thin films of silicon dioxide or silicon nitride between each said electrode and any adjacent zinc oxide or lead zirconate titanate piezoelectric films.

4. The method of claim 1 further comprising the steps of forming a second piezoelectric bimorph using the same microfabrication process used to form the first piezoelectric bimorph, including the steps of forming said second bimorph so as to have one end attached to said substrate and not located over said membrane and so as to have a second end formed on said substrate over said membrane and attached to said second end of said first bimorph.

5. The method of claim 2 further comprising the steps of forming a second piezoelectric bimorph using the same microfabrication process used to form the first piezoelectric bimorph, including the steps of forming said second bimorph so as to have one end attached to said substrate and not located over said membrane and so as to have a second end formed on said substrate over said membrane and attached to said second end of said first bimorph.

3. A method of forming a piezoelectric motion transducer comprising:

forming a membrane in a substrate by etching a pit in a first surface of said substrate;

forming by any suitable microfabrication techniques a piezoelectric bimorph having first and second ends, said bimorph formed on a surface of a substrate opposite said first surface, said bimorph comprising first and second thin film piezoelectric layers sandwiched between a plurality of thin film conductors arranged relative to said this piezoelectric films such that, when said bimorph has said second end freed from said substrate, three dimensional motion can be imparted to said second end by application of suitable voltage differences between pairs of said electrodes, said second end being formed over said membrane;

freeing said second end of said bimorph from said substrate by etching through said membrane to leave said first end of said bimorph integrally attached to said substrate and thereby leaving said second end of said bimorph cantilevered in free space; and

forming a second piezoelectric bimorph using the same microfabrication process used to form the first piezoelectric bimorph, including the steps of forming said second bimorph so as to have one end attached to said substrate and not located over said membrane and so as to have a second end formed on said substrate over said membrane and attached to said second end of said first bimorph.