Three-dimensional structuring of sapphire by sequential He⁺ ion-beam implantation and wet chemical etching

• Main Authors: Crunteanu, A. (Author), Jänchen, G. (Author), Hoffmann, P. (Author), Pollnau, M. (Author), Buchal, C. (Author), Petraru, A. (Author), Eason, R.W (Author), Shepherd, D.P (Author)
• Format: Article
• Language: English
• Published: 2003.
• Subjects: Article
• Online Access: Get fulltext

We present a method for the selective two- and three-dimensional patterning of sapphire using light ion-beam implantation to generate severe lattice damage to depths exceeding 1 µm and subsequent selective wet chemical etching of the damaged regions by hot H₃PO₄. C-cut sapphire crystals were implanted through contact masks using ion fluences of 1×10¹⁶ to 5×10¹⁷ He⁺/cm² and energies up to 400 keV. The etching process is characterized by a high selectivity and a rate of approximately 19 nm/min. Whereas an implantation that produces a continuously damaged pathway results in complete etching from the surface, sole in-depth implantation using only high-energy ions leads to under-etching of the crystalline surface layer. By a combination of these processes we have fabricated three-dimensional structures such as channels and bridges in sapphire.