Etching enhancement in through-implanted SiO2 has been characterized by nuclear-deposited energy independently of implant conditions. An empirical expression has been proposed to describe the etching rate for any implantation. The enhanced etching has been related to the Si-O vibrational frequency shift. Etching enhancement has been found to reflect the structural change in SiO2, and to be a good measure of degradation. The structural change of SiO2 stops and the etching rate reaches a maximum for an ion dose corresponding to nuclear-deposited energy larger than 3.4×1023 eV/cm3. This energy is equal to the total SiO bonding energy (3.8 eV) in a unit volume of SiO2.
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