Microscopy Primer
Light and Color
Microscope Basics
Special Techniques
Digital Imaging
Confocal Microscopy
Live-Cell Imaging
Photomicrography
Microscopy Museum
Virtual Microscopy
Fluorescence
Web Resources
License Info
Image Use
Custom Photos
Partners
Site Info
Contact Us
Publications
Home

The Galleries:

Photo Gallery
Silicon Zoo
Pharmaceuticals
Chip Shots
Phytochemicals
DNA Gallery
Microscapes
Vitamins
Amino Acids
Birthstones
Religion Collection
Pesticides
BeerShots
Cocktail Collection
Screen Savers
Win Wallpaper
Mac Wallpaper
Movie Gallery

Interactive Java Tutorials

Building A Charge-Coupled Device

Explore the steps utilized in the construction of a charge-coupled device (CCD) as a portion of an individual pixel gate is fabricated on a silicon wafer simultaneously with thousands or even millions of neighboring elements. The interactive tutorial examines and illustrates each individual stage in the fabrication of the CCD photodiode sensor element.

Interactive Java Tutorial
ATTENTION
Our servers have detected that your web browser does not have the Java Virtual Machine installed or it is not functioning properly. Please install this software in order to view our interactive Java tutorials. You may download the necessary software by clicking on the "Get It Now" button below.

 

To operate the tutorial, use the blue Forward arrow button to toggle through the various steps necessary to fabricate the CCD. After the second step has been loaded, a Back arrow button appears, which may be used to step backwards through the tutorial. A text window displays information about the individual steps as they appear in the graphics window. When all of the fabrication steps have been completed, simulated photons start bombarding the microlens surface of the CCD. At this point, two sliders appear, which control both the color (wavelength) and the intensity of the photons striking the CCD. Use the Illumination Wavelength slider to vary the photon wavelength, and the Photon Intensity slider to adjust the density of photons striking the microlens surface. Also, the Forward button simultaneously changes into a Stop button that will halt photon movement when clicked. Clicking the Stop changes it into a Start button that will restart photon motion.

Charge-coupled devices (CCDs) are silicon-based integrated circuits consisting of a dense matrix of photodiodes that operate by converting light energy in the form of photons into an electronic charge. Electrons generated by the interaction of photons with silicon atoms are stored in a potential well and can subsequently be transferred across the chip through registers and output to an amplifier. The schematic diagram illustrated in Figure 1 shows various components that comprise the anatomy of a typical CCD.

Fabricated on silicon wafers much like integrated circuits, CCDs are processed in a series of complex photolithographic steps that involve etching, ion implantation, thin film deposition, metallization, and passivation to define various functions within the device. The silicon substrate is electrically doped to form p-type silicon, a material in which the main carriers are positively charged electron holes. Multiple dies, each capable of yielding a working device, are fabricated on each wafer before being cut with a diamond saw, tested, and packaged into a ceramic or polymer casing with a glass or quartz window through which light can pass to illuminate the photodiode array on the CCD surface.

When a ultraviolet, visible, or infrared photon strikes a silicon atom resting in or near a CCD photodiode, it will usually produce a free electron and a "hole" created by the temporary absence of the electron in the silicon crystalline lattice. The free electron is then collected in a potential well (located deep within the silicon in an area known as the depletion layer), while the hole is forced away from the well and eventually is displaced into the silicon substrate. Individual photodiodes are isolated electrically from their neighbors by a channel stop, which is formed by diffusing boron ions through a mask into the p-type silicon substrate.

Contributing Authors

Matthew J. Parry-Hill and Michael W. Davidson - National High Magnetic Field Laboratory, 1800 East Paul Dirac Dr., The Florida State University, Tallahassee, Florida, 32310.


BACK TO DIGITAL IMAGING IN OPTICAL MICROSCOPY

Questions or comments? Send us an email.
© 1998-2013 by Michael W. Davidson and The Florida State University. All Rights Reserved. No images, graphics, scripts, or applets may be reproduced or used in any manner without permission from the copyright holders. Use of this website means you agree to all of the Legal Terms and Conditions set forth by the owners.
This website is maintained by our
Graphics & Web Programming Team
in collaboration with Optical Microscopy at the
National High Magnetic Field Laboratory.
Last modification: Wednesday, Mar 26, 2014 at 02:23 PM
Access Count Since July 28, 2000: 117558
Visit the websites of our partners in digital imaging education:
Visit the Olympus Microscopy Resource Center website. Visit the QImaging website.