Transmission Electron Microscopy (TEM) is the most powerful electron microscopy method. TEM uses electrons for magnification as opposed to optical microscopy, which utilizes visible light. In TEM, an electron beam is amplified and focused using electromagnetic coils while being fired through the specimen. A final set of lenses then magnifies the electron beam before it hits a detector, which in turn produces a visible image of the magnified specimen.

Historically, a fluorescent screen was used as the detector, but now TEM utilizes CCD or CMOS technology to convert the electron beam signals into an image. Through the use of electrons, TEM has the ability to observe objects smaller than 1 nm in size. Such magnification requires an enormous amount of energy, which is usually between 100–200 kV.

TEM’s resolving power has made it a hallmark of microscopy methods in the life sciences, geology, and the metals and semiconductor industries. In life sciences research, TEM allows scientists to explore individual cells to examine their structures and is capable of greater resolution than other electron microscopy methods. Semiconductor devices have become limited in size due to the physical limits of electron tunneling through minute MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) gates. Gate lengths smaller than 20 nm are considered state of the art, and only TEM has the magnification power to resolve manufacturing defects within this range.

The HT7700 is Hitachi High-Technologies’ TEM solution for diverse applications. The HT7700 is a digital TEM designed with capabilities for biomedical, pharmaceutical, agricultural, polymer, chemistry and nanomaterial applications. One main highlight is the software interface, which can perform tasks that simplify research. The auto drive function can recall the location where a previous image was stored, which eliminates the need to search for it manually. A micro-trace function allows the user to differentiate between observed and unexamined areas of the specimen.

JEOL’s JEM-ARM300F TEM trades diversity for raw magnification power. It has been designed to meet advanced materials development demands for atomic-level characterization and chemical mapping. The JEM-ARM300F can magnify down to 63 pm at 300 kV by using a cold-field emission gun in an ultra-high vacuum around the emitter.

Historically, market demand for TEM has not been as high as for SEM. In 2015, the TEM market totaled nearly a quarter of a billion dollars, slightly less than previous years. However, as research in the life sciences and the semiconductor industry increases, so will the need for fine-tuned microscopy, which TEM can provide. Thermo Fisher Scientific is set to enter the TEM market with its pending acquisition of FEI (see IBO 5/31/16).

TEM at a Glance:

Leading Suppliers

• FEI

• JEOL

• Hitachi High-Technologies

Largest Markets

• Semiconductors

• Metals

• Academia

Instrument Cost

• $90,000–$6 Million