NanoLab Research on SiC
![]() |
Chemical Vapor Deposition of SiC thin films |
Activities include thin film growth by CVD, surface
studies, metallization, doping, and etching. Device applications of wide
band gap materials are designed for "extremes" of temperature,
power, radiation, etc. Using novel precursors, crystalline SiC
thin films have been deposited at temperatures as low as 700
°C.
For CVD the current aim of research is the growth of SiC thin film on Si
or SiC substrate from organosilane precursors, which is part of a larger
effort to make superior electronic devices which can work at high
temperature, high power, and a highly corrosive environment. The
precursors utilized in the study are mainly trimethylsilane and
silacyclobutane The structural and chemical properties along with
growth mechanisms of the films have been investigated by variety of
surface |
![]() |
SiCOI for MEMs and Fiber-optic Applications (Lin) |
An increasing demand for micro-sensors that can operate at temperature well above 300°C and often in severe environments (such as those in automotive and aerospace applications, in combustion processes or gas turbine control, and in oil industry) has stimulated the search for alternatives to conventional Si. The research in direct formation of SiC films on insulating substrates (SiCOI structures) in this study finds a very promising technology for producing complicated SiC device structures and provides an excellent alternative material solution for robust MEMS devices operating at high temperature.
Two kinds of SiCOI structures, SiC/poly-Si/SiC/Si3N4/Si for bent-beam strain sensors and SiC/sapphire for electrically passive fiber-optic temperature sensors, have been fabricated, as shown in the attached pictures. The research work in this study extends from SiC thin-film growth using a single organosaline (3MS) precursor and a rapid thermal LPCVD system, photolithography and ICP etch of SiC thin-films, as well as material & device characterization. The techniques used to characterize the as-grown and patterned SiC thin-films and starting substrates include XRD, SEM, AFM, Hall Effect, four-point probe, mercury probe, FTIR, XPS, depth profilometer, UV-Visible-IR absorption/transmission/reflection spectroscopy, and UV-Visible-NIR fiber.
The ease
of deposition and the ability to deposit large area SiC thin-films on
many different insulating substrates make the SiCOI structures very
attractive for many MEMS applications, particularly in connection with
surface micro-machining fabrication techniques. The growth temperature
and 3MS flow rate are the two key parameters on the grain size and the
distribution of grain orientations, which determine the structural,
electrical and optical properties of the SiC thin-films and related
device performance. Moreover, the ability to use electrically passive
poly-SiC fiber-optic temperature sensors gives the unique advantages of
SiCOI for low-cost, robust, high-temperature applications in harsh
environments. |