Abstract
Consideration of candidate materials for MEMS points out silicon - silicon dioxide as a dominant structures at present. This paper deals with 'Silicon Carbide - Aluminum Nitride' (SiC-AlN): a novel alternative to Si-SiO2. The SiC-AlN composition applicability to MEMS can be substantiated by its capability to meet a number of very important MEMS-imposed requirements, such as a good compatibility and a high thermal, electric and mechanical strength of both materials. The two material: one being dielectric and the other - a wide band-gap semiconductor, when integrate in one structure, exhibit the high crystalochemical compatibility and perfectly compatible thermal expansion coefficient. Moreover, both materials have excellent heat conductances which are characteristics of their inherent perfect thermal resistance and low reactivity. In its mechanical strength, SiC yields among semiconductors to diamond only. In addition, the SiC-AlN composition combines strain gauge properties of SiC with piezoelectric properties of AlN. Besides, SiC and AlN both are optically-active up to the UV region of spectrum and may be employed both in light emitters and in photodetectors. Technologically, in application of a MEMS structure, aluminium nitride plays the role of a sacrificial layer to be selectively stripped away by an acid etchant in the epitaxial compositions SiC-AlN. The compatibility of such properties of SiC and AlN, especially in one structure, makes the SiC-AlN composition a promising candidate for MEMS-devices to be designed for the stable-performance operation under rather severe conditions.
