Influence of different etching methods on the structural properties of porous silicon

• Published in: Microelectronics International
• Main Author: Zulkifli F.; Radzali R.; Abd Rahim A.F.; Mahmood A.; Mohd Razali N.S.; Abu Bakar A.
• Format: Article
• Language: English
• Published: Emerald Group Holdings Ltd. 2022
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85130519737&doi=10.1108%2fMI-01-2022-0009&partnerID=40&md5=d907b2ab867ef57415afcf56959950c4

Purpose: Porous silicon (Si) was fabricated by using three different wet etching methods, namely, direct current photo-assisted electrochemical (DCPEC), alternating CPEC (ACPEC) and two-step ACPEC etching. This study aims to investigate the structural properties of porous structures formed by using these etching methods and to identify which etching method works best. Design/methodology/approach: Si n(100) was used to fabricate porous Si using three different etching methods (DCPEC, ACPEC and two-step ACPEC). All the samples were etched with the same current density and etching duration. The samples were etched by using hydrofluoric acid-based electrolytes under the illumination of an incandescent lamp. Findings: Field emission scanning electron microscopy (FESEM) images showed that porous Si etched using the two-step ACPEC method has a higher porosity and density than porous Si etched using DCPEC and ACPEC. The atomic force microscopy results supported the FESEM results showing that porous Si etched using the two-step ACPEC method has the highest surface roughness relative to the samples produced using the other two methods. High resolution X-ray diffraction revealed that porous Si produced through two-step ACPEC has the highest peak intensity out of the three porous Si samples suggesting an improvement in pore uniformity with a better crystalline quality. Originality/value: Two-step ACPEC method is a fairly new etching method and many of its fundamental properties are yet to be established. This work presents a comparison of the effect of these three different etching methods on the structural properties of Si. The results obtained indicated that the two-step ACPEC method produced an etched sample with a higher porosity, pore density, surface roughness, improvement in uniformity of pores and better crystalline quality than the other etching methods. © 2020, Emerald Publishing Limited.