Examples

This page features example processes performed at the Nanoscale Research Facility. Each example has a general process flow with links to the equipment utilized. Click on a title below to scroll to the example details.

2D Materials Processing

Image 1 - Tiled SEM images of randomly placed MoS2 flakes Image 2 - Areas of interest are identified Image 3 - GDS design placed over the SEM tiled image Image 4 - GDS design placed over the SEM tiled image Image 5 - ebeam lithography and metallization via regular lift off process Image 6 - ebeam lithography and metallization via regular lift off process
MoS2 random micro flakes over a SiO2 substrate were mapped and then precisely patterned for transmission line measurements. Starting with a substrate that contains randomly placed MoS2 flakes, an array of fiducial marks are placed via direct milling for subsequent mapping via SEM. Images are then tiled together to create a single high resolution image (image 1). Areas of interest are identified (image2), and a GDS (computer artwork) design is placed over the SEM tiled image (image 3 and 4). The sample then underwent standard ebeam lithography and metallization via regular lift off processing (image 5 and 6).

General Process Flow
  1. Design Layout (created using GDSii editor or Autocad)
  2. Direct Mill Fiducial Marks
  3. SEM Automated Sample Mapping
  4. Electron Beam Lithography
  5. Metal deposition
  6. Inspection by SEM Automated Sample Mapping (refer to step 3)

AlGaN/GaN High Electron Mobility Transistor (HEMT)

high electron mobility transistor (HEMT) device layout high electron mobility transistor (HEMT) die in process
The field of III-N semiconductors has gained a lot of attention for use in high speed and high power switching as well as solid-state sensors. The high electron mobility transistor (HEMT) device layout (image 1) pictured above was fabricated to specification provide by UF researchers. This die layout contains conventional HEMTs with micron and submicron gates fabricated to 250nm gate length. The mask set allowed for three different gate metals to be used on the same die for both materials and process comparisons. A die in process is seen in image 2.

General Process Flow
  1. Design Layout (created using GDSii editor or Autocad)
  2. Mask Fabrication
  3. Photolithography
  4. Plasma Etch
  5. Etch Inspection
  6. Photolithography (refer to step 3)
  7. Metal deposition
  8. Anneal
  9. Photolithography (refer to step 3)
  10. Metal deposition (refer to step 7)
  11. Electron Beam Lithography
  12. Metal deposition (refer to step 7)
  13. Dicing
  14. Die Packaging (manual pick and place and die bonding)
  15. Wire Bonding

Micro Molds for PDMS Stamps

Image 1a - Top view of an anchor shaped photoresist pattern Image 2a - Top view of a photoresist pattern showing decreasingly sized rectangles Image 3a - Top view of an array of rectangles (pillar tops) 1.5 x 6µm photoresist patterned features Image 1b - Oblique SEM view of anchor shaped deep silicon etched pattern Image 2b - Oblique SEM view of deep silicon etched pattern of decending sized rectangles Image 3b - Oblique SEM view of 1.5 x 6µm pillars after deep Si etch
A variety of molds for polydimethylsiloxane (PDMS) casting were created in silicon (Si) wafers. These molds can be used for applications such as, fluidic channels or for micro scale stamps for stamp pattern transfers. The mold is designed using computer aided design (CAD) software, and this design is then transferred to the Si wafer via photolithography. The design is then plasma etched vertically into the Si wafer, producing a high fidelity mold. The etch depth is controlled to the sub-micron level.

General Process Flow
  1. Design Layout (created using GDSii editor or Autocad)
  2. Photolithography
  3. Si Etch
  4. Final Inspection

Nano-CT & 3D Printer

image of a lizard specimen, next to post scanned images of specimen (first one only skeleton, second entire specimen), next to image of enlarged 3D printing of specimen
Specimens were scanned with a GE V|tome|xm 240 CT Scanner to obtain high resolution 3D images of the entire specimen. These 3D images were then converted into 3D printer images called stereolithography (SLT) files and printed with different polymers on an Objet260 Connex2 3D printer. For some specimens, the SLT file was enlarged so micron scale details within the specimen could become visible to the naked eye in the 3D printed model.

General Process Flow
  1. Specimen Scanning
  2. Scan Processing/Editing
  3. 3D Printing

Solid-State Sensors

Solid state sensor for radiation detection chip Solid state sensor for radiation detection design
Solid-state sensors are advancing rapidly and are being placed in a wide array of applications from mechanical movement (accelerometers), sounds (microphones), and bio detection (glucose, pathogen). The device pictured above was fabricated to detect radiation doses and map the dose over an area, it consisted of a dense array of 1000 p-i-n diodes.

General Process Flow
  1. Design Layout
  2. Mask Fabrication
  3. Photolithography
  4. Etch Si Wafer
  5. Implant Dopants (performed by external vendor)
  6. Anneal
  7. Metal deposition
  8. Metal liftoff, inspection
  9. Etch Al Metal
  10. Die Separation
  11. Die Attach to Package (manual process)
  12. Wire Bonding

Spiral Mirror Lens on Flat and Curved Surfaces

Figures 1-3 - Figure 1: Image of spiral mirror with 500 micrometer scale, Figure 2: Image of spiral mirror with 100 micrometer scale, Figure 3: Image of spiral mirror at an oblique angle -no scaleFigure 1: Image of spiral mirror with 500 micrometer scale, Figure 2: Image of spiral mirror with 100 micrometer scale, Figure 3: Image of spiral mirror at an oblique angle -no scale

A spiral designed lens was fabricated on both flat and curved surfaces. The design had a spiral spacing that was graded (with a minimum spacing of 1 micron at the center and 10s of microns at the outer edge) and employed thin gold metal to block a particular wavelength regime. The diameter of the lens spiral was 2mm. The design was created via computer aided desgin (CAD) software and transferred to an electron beam lithography system to create the pattern in a photoresist. The sample later then underwent metallization via regular lift off processing.

General Process Flow
  1. Design Layout
  2. Electron Beam Lithography
  3. Metal Deposition
  4. Metal Liftoff, Inspection