Imprinting porous silicon

Abstract

This chapter describes the capabilities of the direct imprinting of porous substrates (DIPS) technique for patterning and modifying the physical properties of porous silicon films. DIPS can achieve very high-resolution two-dimensional and three-dimensional patterning with feature sizes below 100 nm while eliminating the need for intermediate masking materials and etch recipes that complicate and increase the expense of other patterning techniques. The DIPS process utilizes a reusable master stamp to imprint the desired pattern into porous silicon by directly applying the stamp to the porous substrate with a pressure on the order of 100 MPa. This process is performed in a matter of seconds at room temperature. In addition to enabling the fabrication of patterned porous silicon structures, DIPS also enables morphological control over material properties including porosity, pore size, and refractive index. Examples of designs fabricated by DIPS include grating-coupled wave guides, free-standing particles, and curvilinear structures such as lenses.