Applications of SiC-Based Thin Films in Electronic and MEMS Devices

Abstract

The great development of thin film growth techniques has stimulated the industrial and academic researches about design, fabrication and test of thin film based devices. The replacement of the conventional bulk materials by thin films allows the fabrication of devices with smaller volume and weight, higher flexibility besides lower cost and good performance. It has been shown that the efficiency of thin film based devices is strongly dependent on their structural, electrical, mechanical and optical properties Fraga, a Fraga . At the same time that there is a trend in the miniaturization of electronic and electromechanical devices, there is also a considerable interest in the study of wide bandgap materials to replace the silicon as base material in these devices for harsh applications such as high temperatures and high levels of radiation Fraga, , Yeung, .Silicon carbide SiC has intrinsic properties that make it a material of great interest for microelectronic and MEMS Micro-Electro-Mechanical Systems applications. In the last years, there has been much debate in the literature about how the incorporation of dopant elements such as nitrogen, oxygen, aluminum, boron, phosphorus, etc. during the growth of SiC thin films by chemical vapor deposition CVD or physical vapor deposition PVD processes affects their properties. It has been noticed that the dopant incorporation allows controlling thin film properties such as optical bandgap and electrical conductivity, which are quite attractive because make possible to obtain semiconductor or insulator SiC-based films Alizadeh, Medeiros, . In general, the use of amorphous SiC films has been preferred due to relatively their low growth temperature, which guarantees a larger compatibility with silicon-based technology Hatalis, .Nowadays, SiC-based thin films, such as SiCN, SiCO, SiCNO, SiCB, SiCBN and SiCP, have been extensively used in electronic and MEMS devices either as a semiconductor or as an insulator, depending on the film composition. These films have been shown promising for applications in diodes, thin-film transistors TFTs and MEMS devices Yih, Patil, Hwang, Fraga, c .The goal of this chapter is to discuss the role of in situ incorporation of nitrogen, oxygen, aluminum, boron, phosphorus and argon on the properties of SiC films. Special attention is given to the low temperature SiC growth processes. An overview on the applications of SiCbased thin films in electronic and MEMS devices is presented and discussed. Our recent researches on heterojunction diodes and MEMS sensors are emphasized. . Dopant incorporation during growth of SiC thin films . . In situ dopingMost studies on SiC thin films, especially in their amorphous form, is not focused on intrinsic films. In general, the electrical properties of wide band gap semiconductor materials as the SiC are controlled by introducing dopants into the bulk material Oliveira, . Hence, determining the best material doping concentration is one important issue to be considered during a device development. SiC-based thin ...

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