Detection of Backscattered Electrons with a Deceleration System of the Incident Beam in SEM
Abstract: Distribution of crystal grains with a size of a few tens of nanometers was successfully observed in backscattered electron (BSE) images of SEM with a high contrast. An outermost memory layer of DVD-RAM with a thickness of about 20nm was used as a specimen. The observation was made with JSM-7500F, which was capable of impressing bias voltage on the specimen stage to decelerate the incident electrons to lower the landing voltage. A BSE detector was installed in a position of shorter working distance. Voltage ranges covered in the present experiment were from 0.8 to 30kV for the landing voltage and from 0 to 2kV for the bias voltage. The highest contrast was obtained at the landing and the bias voltage of 0.8kV and 0.5kV, respectively.
Key words: SEM, backscattered electron image, crystalline contrast, low voltage, deceleration mode