Analysis and design of robust power double implanted mosfet on 6H silicon carbide wafers

Abstract

Silicon Carbide is a wide energy gap semiconductor that possesses a combination of parameters that make it ideal for various applications in electronic industry. Its physical properties such as high electric field strength, high saturation drift velocity and high thermal conductivity has placed SiC at the center of renewed focus of semiconductor material and device research amongst other wide energy gap semiconductors. SiC has tremendous advantages because of rapidly maturing technology for making single crystal substrates. In addition, the ability to form a layer of thermal SiO2 on SiC in a similar way to provide the fabrication of Silicon Carbide MOS-based electronic devices. Thus, given the superiority and success of MOS-based devices in applications like high power/temperature electronics and storage devices (nonvolatile memories), SiC is perceived to be the semiconductor of choice with potential to revolutionize the way the electronic systems are designed. In view of current study of power switching devices, the large efforts are concentrated on unipolar devices. These include Field Effect Transistors (FETs) that exist in many types, JFET, MOSFET and MESFET. In low power electronic applications that require high switching speed, the Si MOSFETs have become the dominant technology for many reasons. The relatively low breakdown field in Si and the resistance of drift region that increases rapidly with increasing blocking voltage generally limit the use of Si MOSFETs to 500V and below. The advantages of SiC material properties, in particular breakdown field, makes SiC MOSFETs a very promising candidate for high power switching devices. The specific on-resistance of a SiC power device is expected to be 100-200 times lower than a rated silicon device. Its much lower thermal minority carrier generation implies lower leakage currents and device operation at higher temperatures, arising from self heating due to power dissipation is more tolerable.