1. What is sputtering deposition?

Sputter deposition is a method of depositing thin films by sputtering material from a “target”. Sputtering is a term used to describe the mechanism in which atoms are ejected from the surface of a material when that surface is stuck by sufficiency energetic ions generated by low-pressure gas plasma, usually an argon plasma. The sputtering takes place at a much lower temperature than evaporation. Sputtered atoms ejected into the gas phase in vapor form are not in their thermodynamic equilibrium state and tend to condense on all surfaces in the vacuum chamber including the substrate.

2. Why are thin films important?

There are many useful applications for thin films. We desire to produce properties in a material that are often conflicting in nature if we use one homogeneous material. Semiconductor devices, for example, are fabricated on a thin layer deposited on a semiconductor substrate. The integrated electronic circuits depend on the confinement of electrical charges, which relies on the interfaces between different materials with different electronic properties. There are also many occasions when the properties demanded an engineering application involve features that are different for the surface than that are for the bulk. Depositing metal films and patterning them on the surface are relatively easy to secure electrical connection between semiconductor devices.

3.How does a sputtering system work?

Generally, in sputtering systems ions are generated and directed at a target, then ions sputter targets atoms. The ejected atoms are transported to the substrate and atoms condense and form a thin film. Below image shows the simple schematic of a sputtering system.

Electron Microscope History: Invention & Developmnet (1931)

Electron Microscope Invention and History

Electron microscopes operation is based on imaging backscattered/interacted electrons incident on a surface. These microscopes work on the basis of de Broglie particle-wave duality, where electrons have replaced photons to obtain a resolution 5000 times greater than optical microscopes. Since the first prototype of electron microscope made by German scientists in 1931, nowadays, electron microscopes are capable of two-million-power magnification.

How a Scanning Electron Microscope Works

Who Invented the Electron Microscope?

The first prototype of electron microscope was invented by two German scientists, physicist Ernst Ruska and electric engineer Max Knoll, in 1931 in Technical University of Berlin, which brought 1986 Noble Prize for Ruska. This microscope worked based on imaging transmitted electrons from the sample with 400 power magnification (Figure 1).

Figure 1. Ernst Ruska (left) and the electron microscope he invented in 1933 (right). — Figure 1. Ernst Ruska (left) and the electron microscope he invented in 1933 (right)

The First scanning-tunneling electron microscope was first produced by Manfred Von Ardenne in 1937 (Figure 2). Subsequently, the first commercial transmission electron microscope (TEM) was made by Ruska and Bodo von Borries in Siemens in 1938. In the 1940s, Ruska developed a scanning electron microscope by focusing a scanning electron beam utilizing electromagnetic lenses and collecting scattered electrons, which contained information on the sample topography and structure.

Figure 2. Manfred Von Ardenne and the first scanning-tunneling electron microscope in 1937

Developments of EMs

Afterward, electron microscopes improved rapidly in the 1950s, when developing scanning electron microscope in Charles Oatley’s laboratory at Cambridge University led to the first commercial scanning electron microscope by Cambridge Instruments in 1965.

In 1973, John Venable made the first backscattered electron diffraction pattern (EBDS) by scanning electron microscopy. In 2000, imaging was revolutionized by the introduction of aberration-corrected lenses.

The development of different kinds of electron microscopes continues persistently to obtain higher resolution and accuracy and overcome existing challenges in the way of producing high-quality images from different samples.

Samples of Electron Microscopes

The samples investigated by electron microscopy mainly should be conductive, so there will be no charging effect on the sample surface while imaging. One of the common methods for imaging non-conductive samples is to deposit a conductive coating on their surface. Thus, vacuum coating systems are the best choices for deposition of electron microscopes samples.

Nano-Structured Coatings Co. is a designer and manufacturer of high quality and reliable vacuum coating systems. DSR1 and DSCR are rotary-backed pump sputter coater that capable of coating thin films of conductive metals and carbon for SEM sample preparation.

DSR1

DSCR

Also, high vacuum magnetron sputter coater (DST1) and sputter and carbon coater (DSCT), equipped with turbomolecular pump, are favorable deposition systems for SEM/FESEM sample preparation and deposition of different targets, provided by optional thermal evaporation and plasma cleaning, which is used for making hydrophilic surfaces and TEM grids cleaning.

DST1-170

DSCT

Triple target sputter coater (DST3) with thermal evaporation systems (DST3-T), which are capable of sputtering multiple conductive and insulating targets through DC and RF sputtering, together with thermal evaporation and plasma treatment, provide great opportunities for researchers. For more information, visit our website.