Metallic Nano Electro Mechanically Actuated Gripper and Tunable Nano Photonic Device

Transcription

1 UTD MEMS/NEMS Research Lab. Metallic Nano Electro Mechanically Actuated Gripper and Tunable Nano Photonic Device Jeon-Bon (J-B.) Lee Department of Electrical Enineerin The University of Texas at Dallas Richardson, Texas

2 Objectives Nanoelectromechanical systems (NEMS) Possible to realize smaller mechanical, bioloical and chemical systems Nano rippers Actuators for nano manipulation devices/systems Relatively lare displacement with low actuation voltaes Tunable Nano Photonic Devices New functionalities unachievable with passive nano photonic devices. Real-time, on-demand control can reatly enhance the functionality of photonic devices and systems.

3 UTD Clean Room UTD s Nano Tech Related Facilities 5,866 sq. ft. class 1,000 and 100 Equipped with various processin and metroloy equipment includin evaporators, sputters, RIE, PECVD, LPCVD, mask aliners, e-beam lithoraphy system, SEM, AFM, ellipsometer, Flexus, etc. UTD s Nano Research Facilities Dual beam FIB, XPS, TEM, Field Emission SEM w/ E0beam Lithoraphy System, Ultra Hih Vacuum Wafer Bondin System, Diamond coatin CVD system

4 Sub-µm Metallic Structures E-beam lithoraphy Positive PR (e.., PMMA) Ideal for lift off. Neative PR (SU-8, UVN- 30) Very small exposure dose (~1 µc/cm 2 ), a factor 100 times smaller dose (exp. time)! 500 nm width/spacin and 500 nm thick old comb-drive ~400 nm width ~2 µm thick SU-8 test structures

5 Sub- µm Thermal Actuator Process Electron beam exposure for PMMA Electroplate nickel ~1 hr for 1 µm Removal of PMMA by oxyen RIE Sub-micron thermal actuator Reproducible displacement results Type A : 370 nm by 146 mv 3:1 aspect ratio 1 µm thick PMMA mold Hot arm w = 350 nm L HOT =38 µm

6 Sub- µm Gripper 45um 1.5um um Line: 350 nm Spacin : 1150 nm θ 4.5 um 4.75 um um 5 um L Flex L Cold Displacement [um] Current [ma]

7 NEMS-Enabled Tunable Photonic Crystal What is photonic crystal? Dielectric materials with a periodically varyin index of refraction Photons behaves similar to electrons in a semiconductor crystal; their behavior can be described by a photonic band structure Ability to control/manipulate the flow of electromanetic waves. Tunable Photonic Crystal: conventional approaches Tunin by electro-optic materials (e.. liquid crystal) Tunability is very limited due to small attainable chanes in refractive index ( n/n < 15%). Our approach A radically different approach - Mechanical tunin Photonic bands are extremely sensitive to physical chanes in the photonic crystal structure. Wide tunability by mechanical force Mechanically Controlled Photonic Crystal (McPC)

8 McPC structure is Mechanically Controlled Photonic Crystal Composed of Si rods embedded in flexible polymer such as Polyimide Mechanical tunin by stretchin/releasin McPC with NEMS/MEMS actuators The new material structure is compatible with the conventional semiconductor technoloy In terms of both fabrication process and materials

9 Widely Tunable Beam Steerin Device Refracted beam Γ-M direction Stretchin alon Γ-K direction Unstretched McPC θ r Si 20 10% Elonation alon Γ-K Incident beam θ i Polyimide Refraction Anle (deree) % Elonation alon Γ-K No Elonation Incident Anle (deree) 10% Stretched McPC θ i = 12 o ωa/2πc = 0.39 Tunin of more than 70 o with small mechanical stress (~10%) Switchin between positive & neative refraction reimes

10 Tunable Neative Index Lens Sub-wavelenth resolution, tunability allows chanin focal lenths for adjustable workin distance and dynamically selectin the desired wavelenth or scannin over a rane of frequencies. point source point imae point source point imae Can adjust focal lenth Can also maintain identical focusin characteristics over wide frequency Rane with ω/ω ο up to 30%.

11 McPC Structures Si Pillar Matrix Embedded In Polyimide Film Air Suspended McPC Membrane with Si Ride Waveuide for In-Couplin Manified View of Joint Reion Si Deflection Block McPC Si WG Si Support McPC Neative Refraction Observed in McPC Sub-µm Comb Drive Actuator Si input waveuide liht couplin out liht couplin in inclined 6 o from to free space to McPC Horizontal (λ = 1.54 µm) : no refraction : neative refraction

12 Tunable McPC Applications 3D FPCs Multispectral sensin and detection over extremely wide rane of frequency. Operatin Frequency Feature size Fabrication Visible & Near-IR 200 ~ 500 nm e-beam lithoraphy, reactive ion etch (RIE) Mid & Far-IR 0.5 ~ 10 µm UV lithoraphy, RIE Terahertz 10 ~ 50 µm UV lithoraphy, Si Deep RIE Wide rane beam steerin device Electronically tunable iant neative refraction in 2D slab PC Tunable sub-wavelenth focusin lens NIM can enable sub-wavelenth focusin But the focusin property is stronly wavelenth-dependent. Tunability allows dynamically selectin the desired wavelenth or scannin over a rane of frequencies. Unstretched FPC 5% stretched FPC

13 Acknowledments Fundin National Science Foundation CAREER AWARD National Science Foundation Nanoscale Exploratory Research Proram NIST ATP Proram Contributions UTD MiNDs former/current Lab members J-S. Lee, M. Tinker, D. Park, A. Nallani, Material donation, characterization supports Zyvex, TePla America, MicroChem Other supports UTD Clean room staffs