1. Introduction

%(%+\*z.% !zc%dz!)!z\*z%),+.0\*0z)0!.%(z3\$+/!z,+,1(.%05z\$/z!!\*z+\*/0\*0(5z%\*¥ creasing in the last period due to its excellent mechanical, electrical, optical and chemical properties, which recommend it in difficult and demanding applications.

There are two main fields of applications of SiC. The first one is related to nano electronic [1] or even integrated circuits [2] which are using SiC (in monocrystalline or –sometimespolycrystalline form) as basic structural material for high frequency [3], high power [4], high voltages [5], and/or high temperature devices [6] or combinations thereof [7]. In most of these applications, SiC act as are placement material for silicon which cannot be used under such extreme conditions.

The second area of applications is related to sensors [8fz\* z010+./\_z%^!^z/0.101.!/\_z !2%¥ ces, and/or Microsystems realized (or at least embedding some elements of) micro- and nano electro mechanical systems (MEMS & NEMS). In this area, the usage of SiC (but mainly in ,+(5.5/0((%\*!z\* z)+.,\$+1/z"+.)dz%/z)%\*(5z 1!z0+z%0/z+),0%%(%05z\* z!/5z%\*0!#.%(%¥ ty with Si and Si-based microfabrication technology. In this direction, a lot of miniaturized devices, such as chemical sensors [9], UV detectors [10], MEMS devices [11-13], and even NEMS [14], are using SiC thin films or substrates (6H-SiC or 4H-SiC).

Polycrystalline-SiC (3C-SiC) thin films can be heteroepitaxially grown on Si substrates [14] due to the deposition temperature well below the Si melting point. [15] However, most of MEMS applications require thin films deposition methods at lower temperatures. This is necessary in order to ensure an overall low thermal budget for the entire fabrication of the SiC-based device(s), an essential prerequisite for postprocessing of MEMS structures on top of Si CMOS circuits, which ensures implementation of 'smart sensors'. Plasma enhanced chemical vapor deposition (PECVD) of SiC in an amorphouos state (-SiC) can be such a

solution. Early studies have been done on the structural, optical and electronic properties of this material [16, 17]. More specifically, one of the key challenges for PECVD of SiC for MEMS and NEMS applications is achieving alow residual stress together, if possible, with a high deposition rate and good uniformity [16], [18-20].

The main advantages of PECVD a-SiC deposition can be summarized as follows:


This chapter will focus on the PECVD deposition of a-SiC layers for MEMS/NEMS applications. The chapter is organized in three major parts:

