Diamond: An Ultra-Wide Band Gap Semiconductor for High Power Applications

Wide Bandgap (WBG) semiconductor materials are shaping day-to-day technologyby introducing powerful and more energy responsible devices. These materials have opened the door for building basic semiconductor devices which are superior in terms of handling high voltages, high currents, power, and temperature which is not possible using conventional silicon technology. As the research continues in the field of WBG based devices, there is a potential chance that the power electronics industry can save billions of dollars deploying energy-efficient circuits in high power conversion electronics. Diamond, silicon carbide and gallium nitride are the top three contenders among which diamond can significantly outmatch others in a variety of properties. However, diamond technology is still in its early phase of development and there are challenges involved in many aspects of processing a successful integrated circuit. The work done in this research addresses three major aspects of problems related to diamond technology. In the first part, the applicability of compact modeling and Technology Computer-Aided Design (TCAD) modeling technique for diamond Schottky p-i-n diodes has been demonstrated. The compact model accurately predicts AC, DC and nonlinear behavior of the diode required for fast circuit simulation. Secondly, achieving low resistance ohmic contact onto n-type diamond is one of the major issues that is still an open research problem as it determines the performance of high-power RF circuits and switching losses in power converters circuits. So, another portion of this thesis demonstrates the achievement of very low resistance ohmic contact (~ 10-4 Ω⋅cm2) onto n-type diamond using nano crystalline carbon interface layer. Using the developed TCAD and compact models for low resistance contacts, circuit level predictions show improvements in RF performance. Lastly, an initial study of breakdown characteristics of diamond and cubic boron nitride heterostructure is presented. This study serves as a first step for making future transistors using diamond and cubic boron nitride – a very less explored material system in literature yet promising for extreme circuit applications involving high power and temperature.