A preliminary study of space charge distribution measurements at nanometer spatial resolution

The continuous reduction in size of devices, such as integrated circuits or micro-electro-mechanical systems (MEMS), results in the need to control with better and better resolution the materials involved, and in particular the electrical properties of the insulating and semiconducting parts. In this paper we propose an approach applicable to space charge measurement methods for improving the resolution to the nanometer range by using femtosecond laser pulses. It is shown that a resolution of about 60 nm in SiO₂ can be achieved with thermal and pressure wave propagation methods. Concerning the pulsed electro-acoustic method, the interfacial displacement as small as 100 fm can be measured at THz rate