| Fabricating microelectronic devices using standard semiconductor technology for use in high-temperature (up to 500{dollar}spcirc{dollar}C) electronics offers many challenges for conventional silicon based devices. Silicon carbide (SiC) has gained widespread popularity because it has several advantages over silicon with respect to high-temperature, high-power, high-frequency operation. Although over 200 polytypes of SiC are known to exist, only two polytypes (6H-SiC and 4H-SiC), are currently available in bulk wafer form. Because of their wide bandgap ({dollar}sim{dollar}3.0 eV), high electric field breakdown ({dollar}sim{dollar}2.5 MV/cm), and high saturated electron drift velocity {dollar}rm(sim2.0times10sp7 cmsp2Vcdot s{dollar} at high electric fields), 6H-SiC and 4H-SiC have inherent advantages compared to other semiconductors when operating in high-power, high-frequency applications. When the ambient temperature around the application increases, those advantages are even more pronounced. Despite these advantages, the immaturity of the material growth and processing technology has prevented successful wide-spread commercial application of this unique semiconductor material.; This dissertation begins by providing a general overview of the technology, and then critically evaluates various SiC transistors (Junction Field Effect Transistors (JFETs), Metal Semiconductor Field Effect Transistors (MESFETs), and Metal Oxide Semiconductor Field Effect Transistors (MOSFETs)), in terms of their performance for high-temperature operation. In addition to characterization, critical unit fabrication processes required for device processing, such as Reactive Ion Etching (RIE), oxidation, and dielectric evaluation are investigated. An improved RIE process has resulted in a fast etch rate, with no surface residue. This process is critical for micro-machining of SiC for sensors as well as the development of Monolithic Microwave Integrated Circuits (MMICs) in SiC. Because the failure of dielectrics at high-temperature and high-power has prevented SiC power MOSFETs from reaching the commercial market, unique approaches to solving this problem using low-temperature oxidation in ozone and AlN deposition are also critically evaluated. |
