Effect of silicon resistivity on its porosification using metal induced chemical etching

TL;DR

This study investigates how silicon wafer resistivity influences the morphology of porous silicon formed via metal induced etching, revealing distinct nanostructures based on resistivity levels and doping effects.

Contribution

It provides a comparative analysis of porous silicon structures formed from wafers with different resistivities using MIE, and explains the role of doping in the porosification process.

Findings

High resistivity silicon yields aligned nanowires.

Low resistivity silicon results in interconnected pores.

Photoluminescence suggests quantum confinement effects.

Abstract

A comparison of porous structures formed from silicon (Si) wafers with different resistivities has been reported here based on the morphological studies carried out using scanning electron microscope (SEM). The porous Si samples have been prepared using metal induced etching (MIE) technique from two different Si wafers having two different resistivities. It is observed that porous Si containing well aligned Si nanowires are formed from high resistivity (1-20 $\Omega$cm) Si wafer whereas interconnected pores or cheese like structures are formed from low resistivity (0.02 $\Omega$cm ) Si wafers after MIE. An explanation for the different porosification processes has also been proposed based on the initial doping level where number of dopants seems to be playing an important role on the etching process. Visible photoluminescence have been observed from all the porous samples possibly due to quantum confinement effect.