Effect of Isopropyl Alcohol and Ethylene Glycol in the Anisotropic Etching of Silicon (100) using KOH Solution

Gupta, Disha and Gupta, Nitant and Siju, John and Praveen, Kumar and Manikandanath, NT and Barshilia, Harish C (2014) Effect of Isopropyl Alcohol and Ethylene Glycol in the Anisotropic Etching of Silicon (100) using KOH Solution. Project Report. National Aerospace Laboratories, Bangalore.

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Abstract

Thin silicon wafers have become a basic need for a wide variety of new microelectronic products. Etching technology in thin film process plays an important role in the semiconductor industry. Isotropic/anisotropic etching of silicon has been used to obtain varied microstructures. In this document we have attempted at anisotropic etching of silicon (100) using KOH solution as the etchant. The anisotropic agents used are: isopropyl alcohol (C3H7OH) and ethylene glycol (C2H6O2). Etching has been done by varying different parameters like: concentration of KOH, etching temperatures (ranging from 60-90°C) and etching duration (varying from 10 - 60 min). The etch rate increases with an increase in the concentration of KOH. The etched (100) plane of silicon is covered with pyramidal hillocks till a certain concentration of KOH, whereas, the surface tends to get smoother at higher concentrations of KOH due to isotropic etching. Isopropyl alcohol (IPA) and ethylene glycol, used as anisotropic agents, increase the wettability of the silicon surface thereby giving a smooth texture to the walls of the pyramids. The focus of this work is to conduct a comparative study of KOH etching using IPA and ethylene glycol as anisotropic agents. The effect of hydrogen bubble formation during etching is also studied in detail. It is observed that using a high boiling point anisotropic reagent like ethylene glycol (197.3°C) gives better etched silicon surface as compared to IPA, while 3 gms KOH (7.5% wt.) and 85°C have been found to be the optimized KOH concentration and temperature conditions for good-quality etching.

Item Type: Monograph (Project Report)
Subjects: GENERAL > General
Depositing User: Dr. Harish C. Barshilia
Date Deposited: 21 May 2014 06:08
Last Modified: 17 Aug 2015 10:09
URI: http://nal-ir.nal.res.in/id/eprint/11964

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