Sub-100-nm pattern transfer on compound semiconductor using sol-gel-based TiO2 resist

Boyang Liu; Seng-Tiong Ho

doi:10.1117/12.808647

23 February 2009 Sub-100nm pattern transfer on compound semiconductor using sol-gel-based TiO₂ resist

Boyang Liu, Seng-Tiong Ho

Proceedings Volume 7205, Advanced Fabrication Technologies for Micro/Nano Optics and Photonics II; 720509 (2009) https://doi.org/10.1117/12.808647
Event: SPIE MOEMS-MEMS: Micro- and Nanofabrication, 2009, San Jose, California, United States

Abstract

The possibility to pattern III-V compound semiconductor with nanometer scale is of great interest to photonic, electronic and optoelectronic systems. Typical method for sub-micrometer compound semiconductor dry etching utilizes PMMA or other resist to transfer patterns to SiO² as intermediate masks due to resist's low etching selectivity, especially for ultra-small features. This additional pattern transfer will inevitably increase the potential damage caused by plasma dry etching and the complexity of patterning process. Therefore, it is desirable to find an easier and more effective way to pattern compound semiconductor. In this paper, we report a new approach of direct pattern transfer using Ti(OBuⁿ)₄ solgel derived TiO₂ resist as mask. The optimal dose of TiO₂ resist for e-beam lithography is ~220mC/cm². Thermal stability study of spin-coated TiO₂ shows a good performance as lithography resist even at 300°C, which will have wider applications than conventional resists. Post-annealings at different temperatures are performed to study temperature-dependence of patterned TiO₂ resist as dry-etching mask. The etching selectivity of sample InP compound semiconductor to TiO₂ resist is over 7:1. A variety of sub-100 dry etching patterns with good profile qualities have been obtained. The aspect ratio of etching patterns is over 20:1, and the smallest feature is as small as 20nm with over 600nm deep. This sol-gel derived TiO₂ sipn-coatable nanolithography resist with high etching selectivity and high aspect ratio etching profile provides a novel and convenient way to directly pattern compound semiconductor material for various challenging nano sacle photonic, electronic and optoelectronic applications.

Citation Download Citation

Boyang Liu and Seng-Tiong Ho "Sub-100nm pattern transfer on compound semiconductor using sol-gel-based TiO₂ resist", Proc. SPIE 7205, Advanced Fabrication Technologies for Micro/Nano Optics and Photonics II, 720509 (23 February 2009); https://doi.org/10.1117/12.808647

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