In-lens field emission scanning electron microscopy (In-Lens FESEM) provides topographical information at magnifications of 250x to 1,000,000x, with virtually unlimited depth of field. In-lens FESEM produces clearer, less electrostatically distorted images than SEM, with spatial resolution down to 0.6 nanometers – three times better than regular FESEM and 10 times better than conventional SEM. Other attributes of in-lens FESEM include: - High-quality, low-voltage images with negligible electrical charging of samples (accelerating voltages ranging from 0.5 to 30 kilovolts). - Essentially no need for placing conducting coatings on insulating materials. Applications for in-lens FESEM include: - Semiconductor cross-sections - Gate widths - Gate oxides - Film thickness - Construction analysis - Advanced coatings - Uniformity of thickness - Uniformity of structure Principle of Operation A field emission cathode in the electron gun of a scanning electron microscope provides narrower probing beams at low as well as high electron energy. In conjunction with an in-lens system, this virtually eliminates aberration, resulting in optimal spatial resolution.
