Electronic Materials and Pulsed Laser Deposition
Tim Hogan | hogant@egr.msu.edu | www.egr.msu.edu/~hogant
The Electronic Materials and Pulsed Laser Deposition Laboratory focuses on the fabrication and characterization of electronic materials. Several fabrication routes are studied including thin film materials deposited by pulsed laser deposition, nanowires synthesized by the vapor liquid solid technique, and bulk material synthesis through solid solution chemistry followed by powder processing and densification by spark plasma sintering. We are also studying high temperature, high pressure annealing and synthesis of diamond. Characterization techniques include temperature dependent measurements of electrical conductivity, thermoelectric power (or Seebeck coefficient), thermal conductivity, and Hall effect. Probing stations have been set up for temperature dependent current versus voltage measurements for diamond diodes, and capacitance voltage measurements.
Current projects are further described below:
- Department of Energy, Advanced Research Projects Agency-Energy, “Diamond Diode and Transistor Devices” with T. A. Grotjohn (PI), J. Asmussen, J. Albrecht, C. Wang, T. P. Hogan: In this DOE ARPA-E proposal a technical approach to achieve wide bandgap transistors for high efficiency systems is to utilize diamond deposition and doping technology that is scalable to ultimately provide future generation switching devices at cost targets competitive with conventional semiconductors. Diamond has material properties that exceed those of various wide bandgap semiconductor materials including SiC and GaN. In particular, diamond has a larger bandgap, higher electric field breakdown strength, higher carrier mobility and higher thermal conductivity than the other common wide bandgap semiconductors. This proof-of-concept seedling project has the purpose to demonstrate the potential of diamond electronics to meet the technical specifications and the cost objective of the SWITCHES funding opportunity. The technical demonstrations will be a diamond transistor that operates at 1200 V and 1 A with the path to scale it to 100 A clearly identified.
- National Science Foundation, "DMREF: Doping and Defects in Diamond for Electronics," with T. A. Grotjohn (PI), G. M. Swain, J. Albrecht, T. Schuelke, T. P. Hogan: Diamond’s electronic properties are far superior compared to currently used wide bandgap semiconductor materials. For electronic applications, diamond’s high electron and hole mobility enable high speed and high current operation, its low dielectric constant contributes to high frequency operation, its wide bandgap supports a high breakdown electric field and its high thermal conductivity supports high current operation. To realize the potential of diamond for electronic diodes and transistors it is crucial that the electric field breakdown strength be large and that desired p-type and n-type doping profiles be achieved. The formation of doping profiles with desired variation in both the lateral and vertical directions are key to forming semiconductor junctions and controlling the electric field and breakdown voltages in diode and transistor devices. The goal of this project is to advance the scientific and engineering knowledge needed to form desired doping profiles for diamond electronic devices and to reduce the defects in diamond such that the full high voltage potential of diamond devices is achieved.
