Have you ever wondered where the term "MEMS" came from?
Read J.E. Wood's account:
See a map of who's downloading (last updated 7/11/16)
Nanotechnology: The World Beyond Micro DVD Kit
This kit consists of a DVD and the Nanotechnology: The World Beyond Micro Learning Module with supporting activities and assessments. The film, "Nanotechnology: The World Beyond Micro", is produced and directed by Ruth Carranza of Silicon Run Productions. Dr. Pleil acted as the chair to the advisory board and consulted with Ruth on this project.
Where can I use this kit?
This is a great film for students interested in advanced technology careers or education. Animations on the process steps are very insightful in showing how these devices are actually made and function. Many of the scenes are shot in actual cleanrooms at Intel Corporation, Stanford, and NASA Ames giving students an idea of the various jobs used in nano-fabrication environments.
This film can also be used to give students a reason to consider a STEM career and to focus on learning the material presented in their STEM classes. We recommend all STEM educators to acquire this film, watch it and find ways to excite students. The supporting activities provide reinforcement of the terminology and key concepts of nanotechnology. They also give the students a chance to further explore the field of nanotechnology based on their personal interests.
DNA Microarray Model Kit (formerly GeneChipTM Model Kit)
This kit supports the DNA Microarray Learning Module.
The kit provides participants an opportunity to understand the photolithography fabrication process used to build a GeneChip, a DNA microarray developed by Affymetrix. Participants will simulate fabrication of a three oligonucleotide (oligo) 8 x 8 array. The activity also allows participants to "hybridize" oligos to sample DNA sequences, and to determine the reliability of the DNA microarray test by interpreting the "hybridized" oligos. Participants build a portion of a DNA microarray using a substrate, several masks, and different colored beads, each color representing a nucleotide base (adenine, quinine, cytosine, or thymine).
The DNA Microarray Model Kit contains two array boards, beads that represent DNA's four nucleotide bases, photolithography masks, and test sample DNA models. A DNA Microarray Instructor Guide and Participant Guide are included in the kit. The DNA Microarray Learning Module can be download from the SCME website and printed if additional copies are needed.
Number of participants per kit: 2 groups of 2 to 4 participants per group
How can I use this kit?
This kit can be used has a hands-on demonstration of how a gene-chip is made and to reinforce basic principles of DNA sequencing and identification. These arrays allow one to identify thousands of genes simultaneously with the use of modern biotech methods allowing the creation of microarrays consisting of hundreds or thousands gene sequences. The probe sequences are designed, then fabricated on the chips to detect the complementary DNA fragments of a sample.
BioTech classes, Biology and organic chemistry classes may find this kit exactly what you need to supplement the text book reading and exercises. Combined with the entire BioMEMS suite of educational materials available for download, your students will complete this exercise with a much better understanding of DNA sequencing and the application of technology to identify specific anomalies.
There are several animations available as well to supplement these materials.
This kit is supported by the Crystallography Learning Module.
The included Crystallography Overview Learning Module presents a third activity that allows participants to demonstrate their understanding of the Miller Index. This activity requires that the instructor provide three straight edges (such a rulers or yard sticks) and a rectangular piece of cardboard. See more….
Where can I use this kit? Why would I care?
If you teach a course in MEMS fabrication, mathematics, materials science, semiconductor technology, physics, electronics, chemistry, nano-science or nano-technology, you can easily find a use for this hands-on classroom kit and supporting learning module.
- Crystal Structure (Mathematics, Physics, Chemistry, Earth Science) - Crystals are often taught in earth science classes and kids often make sugar crystals in elementary school. This learning module and associated hands-on activities takes your students much further into the science of crystals. Using the Miller indices students learn how to navigate inside of a crystal and identify its various planes. The application of Cartesian coordinates to describe the structure of crystal planes takes the students to a new level of understanding an application of the classic x,y, and z coordinate system.
- Material Science, physics, electronics, nano and chemistry - Crystals have different physical properties depending on the orientation and structure of the crystal (monocrystalline or polycrystalline). For example, electron flow (current) varies depending on the direction within the crystal and the type of crystal. Mechanical properties such as the bulk modulus of elasticity is different in different directions and etch rates of crystal planes vary depending on the specific plane being etched. The atomic based structure on the nano scale influences these macro properties. The design and fabrication of computer microcircuits (semiconductor technology) and micro systems transducers and actuators (MEMS) leverage these properties.
The three activities of the Crystallography Learning Module:
The instructor-lead "Miller Index Activity" gives the students the tools to navigate within a crystal. Students will demonstrate the direction and orientation associated with different crystal planes so that when they move to the next activity - it all makes sense.
The "Origami Crystal Activity" is based on Dr. Jack Judy's Crystal Origami template. The students assemble a representation of a silicon crystal. This multi-faceted "rhombicuboctahedron" allows students to exercise their fine-motor skills while applying what they learned about Miller indices to the silicon crystal (diamond) structure. This template is loaded with information including silicon etch and silicon dioxide growth as a function of crystal plane orientation, plane orientation, and atomic arrangements as seen from different angles. This activity can be an interesting addition to many STEM courses.
The "Breaking Wafers Activity" allows students to apply destructive testing in learning about crystal structure. Many students have been exposed to the techniques, at least in theory, of cleaving a diamond along different cleavage planes to produce multi-faceted jewels. Silicon crystal has the same structure as diamond jewels. In this activity, students break crystal silicon wafers of two different orientations and using their new knowledge gained in the learning module, identify what orientation each wafer is based on how it breaks.
Application in Microsystems Technology - Microsystems fabrication and design make use of the crystal properties both in the manufacturing of mechanical and electrical components. It is important for technologists entering this multidisciplinary field to have an understanding of these concepts. It is also critical for students to make the connection between the STEM concepts and future employment. You will reduce the frequency of the question "When will I ever use this?"
Microcantilever Model Kit
(formerly the Dynamic Cantilever Kit)
This kit support the Microcantilever Learning Module.
The Microcantilever Model Kit allows students to investigate the motion of a dynamic cantilever under varying masses and various dimensions in order to determine the relationship that expresses the resonant frequency of a cantilever as a function of mass or size. This activity simulates the dynamic mode of operation for microcantilevers used in MEMS sensors.
Students are required to produce a lab report based on their observations that contains the data collected, graphs created showing the relationship of two variables, and the experiment's results. The Microcantilever Model Kit contains cantilevers of different widths, thicknesses and materials. Clamps for mounting the cantilevers to a table, as well as "mass" objects are also included in the kit, along with the Microcantilever Learning Module – Book 1 and 2.
How can I use this kit?
One of the most basic structures used in MEMS is the cantilever. It forms the basis of RF (radio frequency) micro switches, certain types of chemical sensor arrays, and the atomic force microscope. Cantilevers also form various macro structures such as diving boards, balconies, tuning forks, and airplane wings.
Microcantilevers are used to measure the mass (concentration) of individual bacterium collected on a cantilever surface. This dynamic cantilever activity simulates this ability to measure small changes in mass, but at the macro-scale
In this activity students observe how does the width, thickness and length of a cantilever affect its natural frequency. In order to prove this affect, students record the cantilever's movements using a video camera and then analyze video data. What happens as you watch the vibration of a cantilever frame by frame? This is a great method to teach about position, velocity and acceleration vs. time (physics!). Students can even be taught the basics of calculus without them even knowing it!
Once the students acquire the video data, they learn to convert the frame by frame data to resonant frequency - a great hands on problem-solving activity by itself! Converting video observation to a spreadsheet graph of resonant frequency Vs Length, width, thickness, materials and mass added is a lot of fun.
Then - there is the theory! Analyzing and applying the "Mass on Spring" equation (algebra) to the data and extrapolating it to the micro-scale is enlightening. Students see that at this very small scale, using a material such as polycrystalline silicon, the natural frequency of a tiny cantilever is in the megahertz range! This too can be an "ah ha" moment. Now they have enough knowledge to design a cantilever to be ultra-sensitive.
So.... This is not just a physics experiment but ...
Music - how does a tuning fork work? Same concepts!
Mathematics - Measuring resonance as a function of cantilever length yields a non-linear result; one can acquire, plot data and then determine the unknowns in the equation - bulk modulus, and density of the material. Curve fitting anyone?
Engineering and Materials Science - How do the dimensions (L, W, T) affect the resonant frequency? What about stiffness (Bulk or Young's modulus)? How do you design a system that can measure individual e-coli cells and work with off the shelf electronics?
Science and Tech in general - Data Acquisition and analysis - This is so cool for most students because they love to "play" with their digital cameras. Some of the newer smart phones have high enough resolution and frame rate to record this activity. Students learn how to look at videos frame-by-frame and "see" what is going on. Taking this information and transforming it into a graph - wow! It should be noted that places like Sandia National Laboratories use high speed cameras to watch very fast events (like projectiles going through concrete) or Microsystems devices oscillating.
Cantilever-based chemical sensors are used in biotech as well as homeland security applications. Perhaps a BioTech course or Chemistry class can use this activity.
What else does SCME have for you? Well, we do have several short animations and videos which provide great supplemental information:
- "Save My Baby,"
- "Micro Cantilever Array,"
- "Cantilever Resonance Vs Mass Added," and
- "Frames per Second"
Plus lectures are available:
- "How Does a Cantilever Work?" and
- "MicroCantilever Applications Overview"
>>Science of Thin Films>
(Formerly the Rainbow Wafer Kit)
This kit supports the Deposition Overview for Microsystems Learning Module. It can also be used as an activity in the Etch Overview for Microsystems Learning Module.
This kit and supporting learning modules are a study of thin films used to fabricate MEMS or microelectromechanical devices. The learning modules discuss the various types of thin films and how these films are deposited, grown and etched. The kit allows one to further study the characteristics of thin films, specifically silicon dioxide.
The Science of Thin Films Kit uses a rainbow wafer to study the characteristics of silicon dioxide, etch rates and light interference. A rainbow wafer is an oxidized silicon wafer that has been etched using a manual process, resulting in several layers of silicon dioxide (oxide) of different thicknesses. The various thicknesses create a novel rainbow pattern on the wafer. The Rainbow Wafer Kit allows the participants to explore some of the basic concepts of MEMS fabrication such as thermal oxidation, thin film interference, and oxide etch. Participants interpret oxidation graphs, estimate oxide thicknesses, and calculate etch rates. They also observe how light affects the physical appearance of transparent thin films such as silicon dioxide.
The kit contains two rainbow wafers and the Etch Overview for Microsystems Learning Module. See More
Kit refills are available which consist of additional Rainbow Wafers
Where can I use this kit?
SCME's Deposition Overview for Microsystems Learning Module supports several STEM concepts which are needed to understand microsystems fabrication and design. In this module, the deposition of silicon dioxide (a type of glass) is described. The description includes the basic concept of silicon oxidation (similar to the formation of iron oxide, or rust), and the basic chemistry involved in two different oxidation processes – direct oxidation of silicon with oxygen gas or an interaction of the silicon crystal with water vapor. The effect on growth rate (micrometer/hour) as a function of time, temperature, and oxide thickness are explored leveraging concepts such as diffusion, mathematics, and graphing.
To create the striped “rainbow wafer,” the oxide is step-wise etched by lowering the wafer in an HF (hydrofluoric acid) solution for a fixed distance (the height of a stripe) and for a fixed time interval (e.g. 1 minute or 20 seconds). At the end of each time interval, the wafer is lowered one more step. Therefore, moving from the top of the wafer to the bottom, the top stripe was not etched, the next stripe was only etched for one time interval, each stripe below that was etched an increasing amount of time, while the bottom stripe was etched the total time.
The resulting thin oxide film stripes each appear as a different color due to the thin film interference effects of light reflecting off of the top surface of the oxide and the silicon substrate. Students learn how to view the colors for the most accurate estimate of oxide thickness. The colors seen are cross referenced with a color chart to determine the oxide thickness. Using these data, the students plot oxide thickness versus etch time and determine the etch rate by applying a straight line fit to determine the slope (or etch rate). This information is then used to determine the time required to remove a given amount of oxide.
In summary, the students use STEM concepts in the application of thin film deposition, etch rate and thin film measurements as used in microsystems fabrication to solve a typical problem encountered by a MEMS technician. When taught in secondary schools, this learning module ties together STEM to a future job function, giving students an answer to the age old question “When will I ever use that?” and “Why I should care?”
- Chemistry - These wafers are made by first depositing a layer of Silicon Dioxide (SiO2) on a silicon wafer substrate. This is done by exposing the bare crystalline silicon substrate to oxygen. The growth rate is dependent on the crystal orientation, temperature, oxygen concentration and type of oxidation process (i.e. "wet" or "dry" oxidation). Using water vapor to deliver the oxygen ("wet oxidation"), yields a faster deposition rate than using oxygen gas ("dry oxidation"). This comparison is analogous to the formation of rust (FeO2) in humid vs. dry climates. The oxide layer was subsequently removed using a wet etchant containing hydrofluoric acid. The color of the oxide is used to determine the oxide thickness and then analyzed to determine the etch rate.
- Physics - One can use this kit to investigate several optical properties. Thin film interference is responsible for the varying colors. Some of the incident light is reflected off the top surface and some off of the glass/silicon interface resulting in constructive/destructive interference depending on the wavelength of light, index of refraction of the glass and its thickness. This information can also be used in the physics class to plot and determine the etch rate of the process.
- Mathematics - The acquired thickness data can be plotted as a function of etch time. Then a straight line curve fit can be applied, or approximated (best fit through the graphed points). The slope of the fitted line represents the etch rate (oxide removed per minute). One can further delve into the goodness of the fit (is it really linear?). This would be a great capstone for students to apply graphing, and a real-world application of a line function.
- MEMS (Microsystems) Fabrication - The fabrication of microsystems devices include the deposition of optically transparent materials (such as oxides) and the subsequent thinning of these oxides (wet isotropic etching) to change their electrical or optical properties, or the removal of the oxides to free components that need to move (release). Measuring the thickness of these materials is done in the fabrication facility using measurement systems which rely on the thin film interference effect (eye, thin film measurement tools).