@article{deng_zhang_dong_cohen_2016, title={AFM-based 3D nanofabrication using ultrasonic vibration assisted nanomachining}, volume={24}, ISSN={["1526-6125"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000389393500022&KeyUID=WOS:000389393500022}, DOI={10.1016/j.jmapro.2016.09.003}, abstractNote={This paper presents a novel AFM-based 3D nanofabrication process using ultrasonic vibration assisted nanomachining. A set of three dimensional nanostructures on polymethyl methacrylate (PMMA) samples are fabricated with the assistance of high frequency in-plane circular xy-vibration and ultrasonic tip-sample z-vibration. Two methods for fabricating 3D nanostructures were investigated in this study, which are layer-by-layer nanomachining and one pass nanomachining with the depth controlled by setpoint force. Critical parameters in the process are identified, including setpoint force, overlap percentage, amplitude of z vibration and machining speed. By regulating these process parameters, multi-level 3D nanostructures were fabricated by multi-layer machining in vector mode and raster scan mode. Using different setpoint forces for regulating feature depths, other nanostructures, such as convex and concave circles, were fabricated in raster scan mode from gray-scale bitmap pattern images. Under each mode, 3D nanostructure over microscale area can be fabricated in just a few minutes with sub-10 nm resolution in z direction.}, journal={JOURNAL OF MANUFACTURING PROCESSES}, author={Deng, Jia and Zhang, Li and Dong, Jingyan and Cohen, Paul H.}, year={2016}, month={Oct}, pages={195–202} }
 @article{deng_dong_cohen_shih_wang_2016, title={High Rate 3D Nanofabrication by AFM-Based Ultrasonic Vibration Assisted Nanomachining}, volume={5}, ISSN={["2351-9789"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000387592400096&KeyUID=WOS:000387592400096}, DOI={10.1016/j.promfg.2016.08.100}, abstractNote={This paper introduces a high precision 3D nanofabrication approach using ultrasonic vibration assisted nanomachining using an AFM operating in constant height control mode. Nanostructures with 3D features were successfully fabricated on PMMA film with the feature height manipulated through controlling the absolute heights of z-scanner in AFM. Two methods were used to move the AFM tip to create desire features, vector mode and raster scan mode. Relatively simple features, such as stair-like nanostructure with five steps was successfully fabricated in vector mode. Complex nanostructure with discrete height levels and continuous changes were successfully fabricated in raster scan mode. By carefully selecting the machining parameters, the feature dimension and height can be precisely controlled with only small variation from the designed value. Moreover, this paper explores the capability of transferring 3D nanostructures from PMMA film onto silicon substrate. After calibrating the recipe of Reactive Ion Etching (RIE) process, 3D nanostructures are successfully transferred to silicon wafer with controllable selectivity between PMMA and silicon. The results of fabricating 3D structures on silicon substrates show promising potential of many applications, such as mold preparation in nanoimprint lithography.}, journal={44TH NORTH AMERICAN MANUFACTURING RESEARCH CONFERENCE, NAMRC 44}, author={Deng, Jia and Dong, Jingyan and Cohen, Paul and Shih, A and Wang, L}, year={2016}, pages={1283–1294} }
 @article{deng_zhang_dong_cohen_shih_wang_2015, title={AFM-based 3D Nanofabrication using Ultrasonic Vibration Assisted Nanomachining}, volume={1}, ISSN={["2351-9789"]}, url={http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000380512300051&KeyUID=WOS:000380512300051}, DOI={10.1016/j.promfg.2015.09.036}, abstractNote={This paper explores AFM-based 3D nanomachining process assisted by ultrasonic vibration. 3D structures on polymethyl methacrylate (PMMA) substrates are fabricated by ultrasonic vibration-assisted nanomachining process. Two fabrication approaches for 3D structures are investigated in this study, which are layer-by-layer nanomachining and one pass nanomachining with the depth controlled by setpoint force. Critical parameters in the process are identified, including set-point force, overlap rate, amplitude of z vibration and machining speed. By regulating these parameters, stair-like 3D nanostructures are fabricated by multi-layer machining in Vector mode and Raster scan mode. Using different setpoint force for different feature depth, other nanostructures, such as convex and concave circles, are fabricated in Raster scan mode from grey-scale image. Under each mode, 3D nanostructure over microscale area can be fabricated in just a few minutes with the assistance of high frequency in-plane circular xy-vibration and ultrasonic tip-sample z-vibration.}, journal={43RD NORTH AMERICAN MANUFACTURING RESEARCH CONFERENCE, NAMRC 43}, author={Deng, Jia and Zhang, Li and Dong, Jingyan and Cohen, Paul H. and Shih, AJ and Wang, LH}, year={2015}, pages={584–592} }