Characterisation of silicon carbide films deposited by plasma-enhanced chemical vapour deposition

• Published in: Thin solid films 2008-06, Vol.516 (16), p.5189-5193
• Main Authors: Iliescu, Ciprian, Chen, Bangtao, Wei, Jiashen, Pang, Ah Ju
• Format: Article
• Language: English
• Subjects: Amorphous silicon carbide; Applied sciences; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deposition rate; Dry-release; Electronics; Exact sciences and technology; Low stress; Materials science; Mechanical and acoustical properties; Methods of deposition of films and coatings; film growth and epitaxy; Micro- and nanoelectromechanical devices (mems/nems); PECVD; Physical properties of thin films, nonelectronic; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; XeF 2
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2007.07.013

The paper presents a characterisation of amorphous silicon carbide films deposited in plasma-enhanced chemical vapour deposition (PECVD) reactors for MEMS applications. The main parameter was optimised in order to achieve a low stress and high deposition rate. We noticed that the high frequency mode (13.56 MHz) gives a low stress value which can be tuned from tensile to compressive by selecting the correct power. The low frequency mode (380 kHz) generates high compressive stress (around 500 MPa) due to ion bombardment and, as a result, densification of the layer achieved. Temperature can decrease the compressive value of the stress (due to annealing effect). A low etching rate of the amorphous silicon carbide layer was noticed for wet etching in KOH 30% at 80 °C (around 13 A/min) while in HF 49% the layer is practically inert. A very slow etching rate of amorphous silicon carbide layer in XeF 2 –7 A/min– was observed. The paper presents an example of this application: PECVD–amorphous silicon carbide cantilevers fabricated using surface micromachining by dry-released technique in XeF 2.