There are continuing rapid developments in vertical geometry Ga2O3 for high voltage switching applications. Ga2O3 is emerging as a viable candidate for certain classes of power electronics with capabilities beyond existing technologies due to its large bandgap, controllable doping and the availability of large diameter, relatively inexpensive substrates. These include power conditioning systems, including pulsed power for avionics and electric ships, solid-state drivers for heavy electric motors and advanced power management and control electronics. There are already cases where the performance exceeds the theoretical values for SiC. Existing Si, SiC (vertical devices), and heteroepitaxial GaN (lateral devices) enjoy tremendous advantages in terms of process maturity, an advantage that is especially true for Si, where the ability to precisely process the material has resulted in devices such as super-junctions that surpass the unipolar “limit”. Continued development of low defect substrates, optimized epi growth and surface treatments and improved device design and processing methods for Ga2O3 are still required to push the experimental results closer to their theoretical values. Even 3 μm epi layers with doping concentration of 1016 cm-3 should have a theoretical breakdown voltage of ~1800V. The actual experimental value of VB is currently well below the theoretical predictions. Thermal management is a key issue in Ga2O3 power devices for practical high current devices and initial studies have appeared on both the experimental and theoretical fronts. We summarize progress in edge termination design, temperature measurement using thermoreflectance-based thermography to measure the thermal rise and decay of the active diodes, failure under forward bias and development of large current (up to 130A) arrays.
Proton irradiation from the backside of the samples were employed to enhance off-state drain breakdown voltage of
AlGaN/GaN high electron mobility transistors (HEMTs) grown on Si substrates. Via holes were fabricated directly under
the active area of the HEMTs by etching through the Si substrate for subsequent backside proton irradiation. By taking
the advantage of the steep drop at the end of proton energy loss profile, the defects created by the proton irradiation from
the backside of the sample could be precisely placed at specific locations inside the AlGaN/GaN HEMT structure. There
were no degradation of drain current nor enhancement of off-state drain voltage breakdown voltage observed for the
irradiated AlGaN/GaN HEMTs with the proton energy of 225 or 275 keV, for which the defects created by the proton
irradiations were intentionally placed in the GaN buffer. HEMTs with defects placed in the 2 dimensional electron gas
(2DEG) channel region and AlGaN barrier using 330 or 340 keV protons not only showed degradation of drain current,
but also exhibited improvement of the off-state drain breakdown voltage. FLOODS TCAD finite-element simulations
were performed to confirm the hypothesis of a virtual gate formed around the 2DEG region to reduce the peak electric
field around the gate edges and increase the off-state drain breakdown voltage.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.