MICROMACHINING AND MECHANICAL-PROPERTIES OF GAINAS INP MICROCANTILEVERS/

Micro cantilever beams have been fabricated by selective wet etching o f GaInAs/InP heterostructures with InP layer used as a sacrificial lay er and GaInAs regions acting as semiconductor masks and/or etch stop l ayers. With deep front side micromachining, microstructures of one mic ron thick were fabricated and subsequently characterized by means of a nanoindentation system. For GaInAs microstructures, a Young's modulus between 70 and 100 GPa range depending on analysis assumptions was ca lculated. For tri-layered structures with one micron thick sacrificial layer, we faced the problem of stiction. For addressing this issue, w e fabricated several series of beam sets which differ mainly in length and width. A critical length corresponding to the transition between pinned and self-sustaining structures was found and subsequently analy sed in terms of Young's modulus with values consistent with mechanical measurements. (C) 1998 Elsevier Science S.A. All rights reserved.