A high optical-gain β-SiC bulk-barrier phototransistor for high-temperature applications

A high optical-gain beta-SiC phototransistor (PT) with a bulk-barrier structure has been fabricated on a silicon substrate. It demonstrated high optical gains of 145 at 25 degrees C and 106 at 250 degrees C, under a 10-V bias and 10-mu W incident optical power with a wavelength of 500 nm. The high optical gains at elevated temperatures are attributed to not only the excellent high-temperature properties of SIC materials, but also the bulk-barrier structure, in which the formed potential barrier, the short base region and an effect of thinning the quasi-neutral base region to zero thickness lead to a greatly enhanced current gain. The developed beta-SiC built-barrier PT possesses a potential for high-temperature high-gain optical-sensing applications.