Ion Implantation Processes in AlN for Wide Bandgap Semiconductor Power Devices

Current and next-generation power systems require power devices that operate at high voltages and high frequencies beyond the reliable operating limit of the present silicon- and silicon carbide-based power devices. The material properties of AlN permit power devices to operate at these extremes, promoting device shrinkage for automotive applications as well faster switching and more efficient power conversion. Several challenges have heretofore prevented widespread adoption of AlN, most significantly the inability to reliably achieve high n- and p-type conductivity, which is fundamentally important for the performance of semiconductor devices. The overall objective of this proposal is to demonstrate the feasibility of ion implantation to incorporate donor and acceptor species within AlN that would yield technically useful n- and p- carrier concentrations. We will develop processes for the high temperature implantation of these dopant atoms in high quality AlN homoepitaxial thin films grown on AlN substrates. During Phase I, Si+ and Cd+ will be implanted into low dislocation density and low impurity AlN. Implantation profiles will be compared to modeled results of various ions, energies and temperatures. High temperature post-implantation processes will be developed to recover implantation-induced damage and to activate implanted dopants. Contacts to n-type AlN will also be demonstrated and optimized. Achieving the stated objective will enable the manufacture of better power switches and therefore more efficient electricity conversion. With an ever increasing share of our electricity passing through power conversion devices, the success of this program will directly support the Improved Energy Efficiency mission of DOE and can potentially impact every electrical power consumer in the world. New materials are required for a more efficient electrical power devices, such as those used in automobilies, industrial motors, and for electricity conversion between the home the utility grid. AlN, a wide bandgap semiconductor, will be developed for these applications by optimizing electrical properties through ion implantation and high quality control of wafer manufacturing.