Injection, transport, and recombination of charge in semiconductors are important phenomena for governing the operation of microelectronic devices, the function of radiation detectors, and for fundamental studies of the properties of advanced materials. A new technique for the study of these important phenomena is ion-beam induced charge (IBIC) microscopy, which uses a focused, scanned beam of MeV ions. The information provided by this technique is used to study single-event effects in operating integrated circuits (ICs), charge-collection efficiency in radiation detectors that contain defects or other nonuniformities, and radiation damage in semiconductor materials. Detailed information can also be provided for physics-based simulation codes.

As with the related and more widely known technique of electron-beam induced current (EBIC) microscopy, an energetic ion slowing in a sample creates charge in the form of electron-hole pairs. These may drift from their origin under the influence of an internal electric field or diffuse through field-free regions of the sample. In the case of IBIC microscopy, however, a single MeV ion creates a dense path of electron-hole pairs, displaces sample atoms, and may induce sample-atom spallation or fission. In addition to these atomic effects, the other major differences between IBIC and EBIC are that an MeV ion will typically reach depths an order of magnitude deeper in the sample than the electrons used in EBIC and will also undergo relatively minimal sideways scattering. Thus deeply buried structures can be probed with relatively little loss of spatial resolution. The collection of the charge primarily depends on the electric-field distribution from, for example, p-n junctions in an irradiated device and the material properties in the immediate vicinity of the induced charge. The ability to scan a focused MeV ion beam over the area of an integrated circuit, for example, enables the mapping of the combined effect of material properties and field distribution through the measurement of charge-collection efficiencies.