ATOMIC FORCE MICROSCOPE PROBES WITH INTEGRATED RESONANT STRAIN GAUGES

Problem Statement: Since the initial development stages of Atomic Force Microscope, AFMs with optical readout have become the center of attraction for researchers in the field. Despite offering high sensitivity and satisfactory performance, the optical setup is bulky and houses sophisticated and costly optical elements and assemblies that are highly sensitive and inconvenient to work with. This limits utilization of AFM to very specialized applications only by highly trained experts. The bulky head also restricts optical and physical access to the sample under test and only allows flat samples with a limited range of thicknesses to be examined by the microscope. Piezoresistive AFM cantilevers, the most common fully electronic alternative to optically detected AFM cantilevers, suffer from low sensitivity and vulnerability to electronic noise. Proposed Solution: The proposed approach utilizes microscale electromechanical resonant devices as ultra-sensitive strain gauges providing electronic cantilever deflection data along with orders of magnitude higher sensitivity and lower noise vulnerability compared to the piezoresistive cantilevers. In this manner sophistication of AFM and its optical readout setup is replaced by MEMS sensors integrated on the probe cantilever chip. Commercial Applications and Other Benefits: Upon successful development the proposed probes can be used along with the existing AFM systems in frequency modulated mode offering unprecedented simplicity and flexibility. Furthermore, the probes with integrated MEMS sensors, along with the computer interfaced fully electronic readout modules that will be developed under this project can constitute a simple ultra-low cost and easy to use AFM that could be an add-on to any probe station or microscope. The proposed technology could therefore revolutionize the AFM industry by enabling highly affordable and easy to use AFM systems applicable in a variety of new areas. The low price, potentially starting below $5k could encourage addition of AFM capabilities in a large number of research and educational labs as well as manufacturing environments nationwide. Key Words: Atomic Force Microscopy, AFM, MEMS, Nanomechanics, Electromechanical Resonator, Resonant Strain Gauge, AFM Cantilever, MEMS Cantilever Summary for Members of Congress: The Atomic Force Microscope (AFM) has been credited for opening the world to nanotechnology. This project aims at development of a new class of AFMs offering significant cost reduction and ease of use allowing widespread use of AFM techniques in state of the art research, development, and manufacturing.