Concepts and Definitions¶

Terms used across these guides. Each is defined once, on exactly one page, and listed here with a link to that page. Grouped by domain.

Electron and probe microscopy¶

Transmission Electron Microscopy (TEM): A characterization technique in which a beam of electrons is transmitted through a specimen thinner than roughly 100 nm to form an image or diffraction pattern, resolving internal structure and composition below 0.2 nm. → Full page
Scanning Electron Microscopy (SEM): A characterization technique in which a focused electron beam is scanned across a specimen surface, with detectors collecting emitted electrons and X-rays to image surface topography and composition down to about one nanometre. → Full page
Focused Ion Beam: A characterization and sample-preparation method that uses a focused gallium ion beam to mill, cross-section, or lift out a site on a specimen, while a coincident SEM column images the same location during the cut. → Full page
Atomic Force Microscopy (AFM): A surface metrology technique in which a probe on a flexible cantilever is scanned across a sample at constant force, recording the vertical motion required to produce a calibrated three-dimensional height map. → Full page
TEM Sample Preparation: A sequence of mechanical grinding, dimpling, and argon ion milling that thins a bulk specimen to electron transparency, typically below 100 nm, so that it can be imaged in a transmission electron microscope. → Full page

Optical and thin-film metrology¶

Optical Profilometry: A non-contact surface metrology technique that reconstructs a three-dimensional height map from optical signals, reporting roughness, step height, and topography over fields from micrometres to tens of millimetres. → Full page
Spectroscopic Ellipsometry (SE): An optical characterization technique that measures the change in polarisation state of light reflected from a surface, and derives thin-film thickness and optical constants by fitting that change to a layer model. → Full page
Photoluminescence Spectroscopy (PL): An optical characterization technique in which a specimen is excited with light and the resulting emission is recorded as a spectrum or as a decay versus time, reporting electronic structure, defects, and carrier lifetime without contacting the sample. → Full page
Digital Microscopy: An optical inspection method in which a camera-based microscope captures fully focused images of a surface, with on-screen 2D measurement and optional 3D reconstruction, without requiring the operator to look through eyepieces. → Full page
Spatial Light Modulation: An optical method in which a liquid-crystal-on-silicon panel imposes a programmed phase pattern on a reflected beam, shaping wavefronts for holography, beam steering, and structured illumination. → Full page
Wide-Area Coordinate Measurement: A dimensional metrology method in which a tracked handheld probe records 3D coordinates of a part that is too large, or too awkward, to place on a fixed coordinate measuring machine, reporting distances, GD&T, and optional laser-scanned shape. → Full page
X-ray Diffraction (XRD): A characterization technique in which a collimated X-ray beam is scattered by a crystalline material, and the angles and intensities of the diffracted beams are used to identify phases, measure lattice spacing, and assess crystallographic orientation. → Full page
X-ray Reflectivity (XRR): A specular X-ray measurement at grazing incidence in which interference fringes from a layered film are fitted to obtain thickness, density, and interface roughness without destroying the sample. → Full page

Surface analysis¶

Secondary Ion Mass Spectrometry (SIMS): A surface analysis technique in which a focused primary ion beam sputters a specimen, and the ejected secondary ions are mass-analysed, yielding elemental and molecular composition as a function of depth with trace-level sensitivity. → Full page
Sputtered Neutral Mass Spectrometry (SNMS): A variant of secondary ion mass spectrometry in which sputtered neutral atoms are ionised after they leave the surface, so that the detected signal is less dependent on the local ionisation probability and depth profiles can be quantified more directly. → Full page

Porosity and surface area¶

Gas Sorption Analysis - also BET Surface Area Analysis: A characterization technique in which the quantity of a probe gas adsorbed by a solid is measured as a function of relative pressure at constant temperature, yielding specific surface area by the Brunauer-Emmett-Teller method and a pore size distribution. → Full page
Sample Degassing - also Adsorption Pretreatment: A sample preparation step in which physisorbed water and gases are removed from a solid by heating it under vacuum or flowing inert gas, so that the surface is clean before an adsorption isotherm is measured. → Full page

Reliability and calibration¶

Environmental Stress Testing - also Temperature and Humidity Cycling: A reliability test method in which a component or assembly is held at, or cycled between, controlled temperature and humidity conditions in order to provoke failures that appear only after thermal or moisture stress. → Full page
Deadweight Tester - also Pressure Balance: A primary pressure standard in which a known pressure is generated by balancing calibrated masses on a piston of known effective area, so that pressure is derived from mass, local gravitational acceleration, and area rather than from a sensor. → Full page

Additive manufacturing¶

Fused Deposition Modeling (FDM): An additive manufacturing process in which thermoplastic filament is melted and extruded through a heated nozzle, and deposited layer by layer to build a three-dimensional part. → Full page
Anisotropy in Additive Manufacturing: The direction dependence of a printed part's mechanical properties, arising because material deposited within a layer is continuous while adjacent layers are joined only by polymer chain interdiffusion across a partially remelted interface, so strength measured across the build direction is lower than strength measured within a layer. → Full page

Subtractive manufacturing¶

CNC Machining - also Computer Numerical Control Machining: A family of subtractive manufacturing processes in which material is removed from a solid workpiece by a cutting tool whose position and speed are commanded by a numerical control program, producing a part whose dimensions derive from the machine's positioning accuracy rather than from a mould or a deposition path. → Full page
CNC Milling: A subtractive manufacturing process in which a rotating cutting tool removes material from a workpiece held on a table, with tool and table positions driven by a numerical control program. → Full page
CNC Turning: A subtractive manufacturing process in which a workpiece is rotated in a chuck while a stationary cutting tool is fed against it under numerical control, producing cylindrical features such as diameters, faces, grooves, and threads. → Full page

Microfabrication¶

Laser Micromachining: A fabrication process in which a pulsed laser ablates material to structure, drill, or cut a substrate, removing metal, ceramic, glass, or polymer with little heat transfer into the surrounding part. → Full page
Photolithography: A patterning process in which ultraviolet light transfers a photomask image into a photoresist film on a wafer or coupon, so that subsequent etch or deposition steps only affect the regions defined by that image. → Full page
Nanoimprint Lithography: A patterning process in which a master stamp is pressed into a thermoplastic or UV-curable resist so that the stamp's topography is replicated in the resist, then used as a mask or as a functional structure. → Full page
Wafer Scribing: A sample-preparation method in which a carbide or diamond wheel scores a straight line on the top face of a brittle wafer or coupon so that the piece can be cleaved along that line. → Full page
Conductive-Ink PCB Printing: A desktop fabrication method in which conductive ink is dispensed onto a substrate to form traces, then cured, with optional drilling and solder-paste dispensing, so a circuit board can be prototyped without a photomask or an etch. → Full page

Electrical characterization¶

On-Wafer Probing: An electrical characterization method in which needle or RF probes contact pads on a bare die or wafer so that current, voltage, capacitance, or high-frequency parameters can be measured before the device is packaged. → Full page
Impedance Analysis: An electrical characterization method that measures the complex impedance of a component or material as a function of frequency, yielding resistance, reactance, capacitance, inductance, and related parameters from a four-terminal-pair measurement. → Full page
Vector Network Analysis: An RF characterization method that measures the complex scattering parameters of a two-port network, reporting how the device reflects and transmits a 50 ohm stimulus as a function of frequency. → Full page
Closed-Cycle Optical Cryostat Measurement: A characterization method in which a sample is cooled in vacuum by a closed-cycle cryocooler, without liquid helium, so that electrical transport and optical measurements can be made from a few kelvin to above room temperature. → Full page
Seebeck Coefficient Measurement: An electrical characterization method that measures the voltage generated by a temperature gradient across a sample, the Seebeck coefficient, and the electrical resistivity by a four-terminal method, usually as a function of temperature. → Full page
Benchtop Electrical Measurement: General-purpose electrical measurement in which a digital multimeter, an arbitrary function generator, and a digital oscilloscope source and record voltage, current, and waveforms on the bench, without a probe station or a network analyzer. → Full page

Microelectronic packaging¶

Die Attach: The process of placing a semiconductor die onto a substrate or package and joining it with adhesive, eutectic solder, or thermocompression, establishing mechanical support and, where required, a thermal or electrical path to the package. → Full page
Thermosonic Wire Bonding: A packaging process that joins a fine gold wire to a die pad and then to a package lead using ultrasonic energy and heat, forming a metallurgical bond without melting the wire. → Full page

Industrial automation and control¶

Programmable Logic Controller (PLC): An industrial computer that reads discrete and analog inputs from field sensors, evaluates a control program on a fixed repeating scan, and drives outputs to actuators, built for continuous operation in an electrically noisy plant environment with deterministic timing and field-serviceable wiring. → Full page
Ladder Logic: A graphical programming language for programmable logic controllers in which control relationships are drawn as rungs between two power rails, each rung evaluating a combination of input conditions on the left to energise an output coil on the right, derived from the relay wiring diagrams the language replaced. → Full page
Mechatronics Learning System: A modular set of instructional workstations that reproduce the stations of an automated production line, each driven by an industrial programmable logic controller, so that learners practise sequencing, sensing, actuation, and interfacing on production-grade components rather than on simulations. → Full page
Go/No-Go Gauging: An inspection method that answers whether a dimension falls inside its tolerance band, without reporting the dimension itself. Because the decision is binary it can be automated with simple sensors and acted on immediately by a controller. → Full page

How this glossary is organised¶

A term belongs to exactly one page. That page carries the full definition; this page lists the term and links to it. If a word is missing, start from the technique that uses it, or ask lab staff.