Laterally stacked porous silicon multilayers for subquart micron period UV gratings

Abstract

A novel method was presented to prepare porous silicon Bragg grating structures. With this technique the grating period can be easily tuned in a wide range. In the porous silicon multilayer formation there is no theoretical limit for the period to be lowered to even below 100 nm. Both phase and mixed type (amplitude and phase) optical grating are demonstrated. Another unique feature of these structures is, that contrary to the case of commonly used porous silicon layers, here the pores are lying parallel to the wafer surface. This might be a valuable asset e.g. in microfluidic-type sensor development. The paper discusses design and processing constraints. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.