Etching rate of silicon nanowires with highly doped silicon during metal-assisted chemical etching

The fabrication of silicon nanowires (SiNWs) by metal-assisted chemical etching (MACE) has been widely studied in a variety of fields. SiNWs by high-doped silicon are potential materials to be applied in thermoelectric, lithium-ion batteries and sensors. However, existing studies on the etching characteristics of high-doped silicon are limited and miSunderstandings are existing. In this study, through the comparison of three types of silicon with different concentrations, it was found that the loss of SiNWs by low-doped and medium-doped was little but the loss for high-doped silicon was significant. Contrary to existing reports, we clarify that the etching rate of high-doped silicon was the highest among them through measurements and calculations, although the observed length was the smallest. The differences between supposed generated SiNWs and measured SiNWs can be assumed as the lateral etching of high-doped silicon. In addition, the cluster morphology of high-doped silicon also suggested severe lateral etching. Therefore, the etching characteristics of high-doped silicon and the mechanism need to be re-understood to control reactions and obtain expected SiNWs.