Beta-SiC has been considered for a variety of applications for electronic and electromechanical devices. Its wide band gap (2.2-eV), high dielectric strength, and high thermal conductivity have already been utilized to fabricate devices such as high temperature MQSFETs.1 Additional devices of interest may include IMP ATT diodes and electromechanical sensors. In the fabrication of all these devices, a method of controllable and selective etching is required. However, β-SiC is a rather chemically inert material making patterning difficult. Currently, the most effective technique for etching SiC is reactive ion etching (RIE) with reported etch rates as high as 0.2μm/min.2 We report the use of nonthermally induced UV laser controlled photoelectrochemical etching to achieve etch rates of β-SiC as high as 100 μm/min. This maskless procedure involves photogenerated carriers at an externally biased semiconductor-electrolyte interface which controls the etch rate of the substrate. The spectral dependence of the optical absorption coefficient of β-SiC suggests that laser wavelengths of <300 nm will be most effective in controlling the etch rates.
© 1990 Optical Society of AmericaPDF Article