An electron microscope is a microscope that uses a beam of electrons as a source of illumination. They use electron optics that are analogous to the glass lenses of an optical light microscope to control the electron beam,for instance focusing them to produce magnified images or electron diffraction patterns. As the wavelength of an electron can be up to 100,000 times smaller than that of visible light,electron microscopes have a much higher resolution of about 0.1 nm,which compares to about 200 nm for light microscopes. Electron microscope may refer to:
Photolithography is a process used in the manufacturing of integrated circuits. It involves using light to transfer a pattern onto a substrate,typically a silicon wafer.
A scanning electron microscope (SEM) is a type of electron microscope that produces images of a sample by scanning the surface with a focused beam of electrons. The electrons interact with atoms in the sample,producing various signals that contain information about the surface topography and composition of the sample. The electron beam is scanned in a raster scan pattern,and the position of the beam is combined with the intensity of the detected signal to produce an image. In the most common SEM mode,secondary electrons emitted by atoms excited by the electron beam are detected using a secondary electron detector. The number of secondary electrons that can be detected,and thus the signal intensity,depends,among other things,on specimen topography. Some SEMs can achieve resolutions better than 1 nanometer.
Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a grid. An image is formed from the interaction of the electrons with the sample as the beam is transmitted through the specimen. The image is then magnified and focused onto an imaging device,such as a fluorescent screen,a layer of photographic film,or a detector such as a scintillator attached to a charge-coupled device or a direct electron detector.
An excimer laser,sometimes more correctly called an exciplex laser,is a form of ultraviolet laser which is commonly used in the production of microelectronic devices,semiconductor based integrated circuits or "chips",eye surgery,and micromachining.
Thomas Eugene Everhart FREng is an American educator and physicist. His area of expertise is the physics of electron beams. Together with Richard F. M. Thornley he designed the Everhart–Thornley detector. These detectors are still in use in scanning electron microscopes,even though the first such detector was made available as early as 1956.
Electron-beam lithography is the practice of scanning a focused beam of electrons to draw custom shapes on a surface covered with an electron-sensitive film called a resist (exposing). The electron beam changes the solubility of the resist,enabling selective removal of either the exposed or non-exposed regions of the resist by immersing it in a solvent (developing). The purpose,as with photolithography,is to create very small structures in the resist that can subsequently be transferred to the substrate material,often by etching.
Nanolithography (NL) is a growing field of techniques within nanotechnology dealing with the engineering of nanometer-scale structures on various materials.
Dip pen nanolithography (DPN) is a scanning probe lithography technique where an atomic force microscope (AFM) tip is used to directly create patterns on a substrate. It can be done on a range of substances with a variety of inks. A common example of this technique is exemplified by the use of alkane thiolates to imprint onto a gold surface. This technique allows surface patterning on scales of under 100 nanometers. DPN is the nanotechnology analog of the dip pen,where the tip of an atomic force microscope cantilever acts as a "pen",which is coated with a chemical compound or mixture acting as an "ink",and put in contact with a substrate,the "paper".
Focused ion beam,also known as FIB,is a technique used particularly in the semiconductor industry,materials science and increasingly in the biological field for site-specific analysis,deposition,and ablation of materials. A FIB setup is a scientific instrument that resembles a scanning electron microscope (SEM). However,while the SEM uses a focused beam of electrons to image the sample in the chamber,a FIB setup uses a focused beam of ions instead. FIB can also be incorporated in a system with both electron and ion beam columns,allowing the same feature to be investigated using either of the beams. FIB should not be confused with using a beam of focused ions for direct write lithography. These are generally quite different systems where the material is modified by other mechanisms.
Secondary electrons are electrons generated as ionization products. They are called 'secondary' because they are generated by other radiation. This radiation can be in the form of ions,electrons,or photons with sufficiently high energy,i.e. exceeding the ionization potential. Photoelectrons can be considered an example of secondary electrons where the primary radiation are photons;in some discussions photoelectrons with higher energy (>50 eV) are still considered "primary" while the electrons freed by the photoelectrons are "secondary".
Interference lithography is a technique for patterning regular arrays of fine features,without the use of complex optical systems or photomasks.
Haroon Ahmed FREng,is a British Pakistani scientist in specialising the fields of microelectronics and electrical engineering. He is Emeritus Professor of Microelectronics at the Cavendish Laboratory,the Physics Department of the University of Cambridge,Honorary Fellow of Corpus Christi College,Cambridge,and Fellow of the Royal Academy of Engineering.
Electron-beam-induced deposition (EBID) is a process of decomposing gaseous molecules by an electron beam leading to deposition of non-volatile fragments onto a nearby substrate. The electron beam is usually provided by a scanning electron microscope,which results in high spatial accuracy and the possibility to produce free-standing,three-dimensional structures.
Jonathan Harris Orloff is an American physicist,author and professor. Born in New York City,he is the eldest son of Monford Orloff and brother of pianist Carole Orloff and historian Chester Orloff. Orloff is known for his major fields of research in charged particle optics,applications of field emission processes,high-brightness electron and ion sources,focused ion and electron beams and their applications for micromachining,surface analysis and microscopy and instrumentation development for semiconductor device manufacturing.
X-ray lithography is a process used in semiconductor device fabrication industry to selectively remove parts of a thin film of photoresist. It uses X-rays to transfer a geometric pattern from a mask to a light-sensitive chemical photoresist,or simply "resist," on the substrate to reach extremely small topological size of a feature. A series of chemical treatments then engraves the produced pattern into the material underneath the photoresist.
Thermal scanning probe lithography (t-SPL) is a form of scanning probe lithography (SPL) whereby material is structured on the nanoscale using scanning probes,primarily through the application of thermal energy.
Liquid-phase electron microscopy refers to a class of methods for imaging specimens in liquid with nanometer spatial resolution using electron microscopy. LP-EM overcomes the key limitation of electron microscopy:since the electron optics requires a high vacuum,the sample must be stable in a vacuum environment. Many types of specimens relevant to biology,materials science,chemistry,geology,and physics,however,change their properties when placed in a vacuum.
A probe tip is an instrument used in scanning probe microscopes (SPMs) to scan the surface of a sample and make nano-scale images of surfaces and structures. The probe tip is mounted on the end of a cantilever and can be as sharp as a single atom. In microscopy,probe tip geometry and the composition of both the tip and the surface being probed directly affect resolution and imaging quality. Tip size and shape are extremely important in monitoring and detecting interactions between surfaces. SPMs can precisely measure electrostatic forces,magnetic forces,chemical bonding,Van der Waals forces,and capillary forces. SPMs can also reveal the morphology and topography of a surface.
Jabez Jenkins McClelland is an American physicist. He is best known for his work applying the techniques of laser cooling and atom optics to nanotechnology. This work involved expanding the number of atomic species that could be laser cooled from the alkalis and a few alkaline earth and noble gas species,to transition metals such a chromium and rare earths such as erbium. In the early 1990s he and colleagues showed that the nodes of an optical standing wave could act as lenses,focusing chromium atoms as they deposit onto a surface to create a permanent grating structure whose periodicity is precisely tied to an atomic resonance frequency,making it a useful nanoscale length standard. In the early 2000s his team showed that laser cooled atoms can produce a very high brightness ion beam when ionized just above threshold,and used this technique to realize a high resolution lithium ion microscope.
