Crystallinity-retaining removal of germanium by direct-write focused electron beam induced etching

Abstract

In this work, a well-controllable, direct-write, resistless, and crystallinity-retaining etching process for germanium using a focused electron beam with nanometer resolution has been developed. This process allows for precise, local, and efficient removal of germanium from a surface without showing any spontaneous etching effects. This focused electron beam induced etching process of germanium substrates employs pure chlorine gas as etchant. The presented process was carried out in a conventional scanning electron microscope equipped with a custom-tailored gas injection system. The etch rate of this etching process was observed to be up to 0.32 μm3 min−1 or 12 nm min−1 for an area of 1.5×1.5 μm2. The influence of various etching parameters such as electron beam current, acceleration voltage and chlorine gas flow on the etch rate as well as the shape of the etch pits have been studied systematically by atomic force microscopy analysis. It is demonstrated that etching of amorphous germanium films can be performed significantly faster (∼8 times) than etching of crystalline germanium. Finally, a comparison between silicon etching and germanium etching by chlorine is presented.

Synthesis and electroplating of high resolution insulated carbon nanotube scanning probes for imaging in liquid solutions

“…EBIE can also be performed on non-Si based materials. Goler et al [29] demonstrated etching of graphene nanostructures, Roediger et al [30] has demonstrated removal of Ge, Schoenaker et al [31] has etched Ti and Ganczarczyk et al [32] has etched GaAs to list a few recent discoveries. To perform this step, various parameters were investigated on test SiN x samples including: variable electron beam energy and current, as well as the pump-down time in the chamber (water concentration and residual carbonaceous gases).…”

Nanoestructuras funcionales fabricadas mediante un haz de electrones o iones focalizado

“…Como ya hemos comentado, el FEB no tiene un efecto de pulverizado físico a los voltajes de aceleración con los que se trabaja en un SEM convencional y los procesos de ataque se basan en la reactividad del gas adsorbido y en la volatilidad de los productos de la reacción. El proceso ha sido demostrado en materiales como por ejemplo, SiO 2 , SiN, Al, Cr, CrO x , TaN, GaAs y Ge [26][27][28][29][30][31][32][33]…”

Local, direct-write, damage-free thinning of germanium nanowires

“…In order to achieve a high process control only a small electron beam current of 350 pA has been employed (the etch rate strongly depends on the electron beam current used 30 ). In order to achieve a high process control only a small electron beam current of 350 pA has been employed (the etch rate strongly depends on the electron beam current used 30 ).…”