Monte Carlo simulation of size effect on the dielectric strength of α-quartz

The size effect (SF) in a dielectric subjected to a surface space charge field has been defined as the slope of the curve ln(V_s/r) vs ln(r), where V_s and Γ are the critical surface potential and length of the sample, respectively. SF is an important material parameter affecting the breakdown voltage, the space charge detrapping field, the friction coefficient, the wear and the fracture toughness of the dielectric. In the present work, the SF effect was investigated. The experimental study was carried out in an SEM (scanning electron microscope) using an electron beam to bombard the dielectric. The space charge distributions for different sizes are obtained separately from macroscopic equations and microscopic simulation