Electron-beam-induced current and atomic force microscopy studies on silicon etch steps created by reactive ion etching and reactive ion beam etching

Abstract

Reactive ion etching and reactive ion beam etching are common anisotropic etch processes in silicon microdevice fabrication. Unfortunately, they are also known to create electrically active defects in the bulk material. It is possible to detect these active defects with the electron-beam-induced current (EBIC) mode of the scanning electron microscope and to follow the etch design with the measured EBIC line scans. This is due to a lower EBIC signal (reduction by defects) in the etched area than in the protected area. The EBIC signal curves show signal bumps and trenches at the etch edges, in correlation to contamination walls measured by the atomic force microscope. The origin and shape of both signals, electrical and geometric, will be discussed and found as an effect of the higher density of ions in the edge areas.