We report on AlGaN channel metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) for the first time. The insulator of 10-nm SiN x was deposited by plasma enhanced chemical vapor deposition, which induced a low reverse and forward Schottky leakage. A very high breakdown electric field of 1.8 MV/cm was reached with a gatedrain distance of 2 µm. The breakdown voltage increased non-linearly with the gate-drain distance and reached 1661 V with a gate-drain distance of 20 µm. As temperature increases from 25 to 275°C, the saturation drain current decreases slightly by 20% from 211 to 169 mA/mm and the onresistance increases only by 24%.
SUMMARYA new large dynamic-range variable gain amplifier (VGA) with improved dB linearity is presented. The traditional cascade VGA has the disadvantages of gain mismatch between sub-stages and difficulty of employing mismatch cancelation or suppression algorithms. In this paper, switch arrays were used to make the sub-stages or called gain cells in the coarse-tuning stage (CTS) work independently and therefore prevent the integral operation of the gain errors. Then, a second-order mismatch-shaping DEM was applied conveniently to the CTS and shown to be a useful design technique in improving the dB-linearity performance. The cascade VGA and its second-order mismatch-shaping DEM had been integrated in a 2.4-GHz receiver chip which was fabricated in a 0.18-μm CMOS technology with a supply voltage of 1.8 V. Measurement results showed that the gain errors were significantly reduced with second-order mismatch-shaping DEM with respect to the traditionally thermometric decoding over a temperature range of [À40, 80]°C.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.