Activation of Mg implanted in GaN by multicycle rapid thermal annealing

Abstract

A long-standing goal of GaN device research has been the development of a reliable, well-controlled process for p-GaN formation by ion implantation. Results to date have indicated an activation of 1% or less using high-temperature rapid thermal annealing (RTA) techniques and coimplantation. Although Mg is a relatively deep acceptor, this is still much less than the theoretically achievable value (8.2% based on the 160 meV acceptor level). A multicycle RTA process is presented that is capable of achieving up to 8% activation of the Mg-implanted GaN. This approaches the theoretical value, and represents a significant step in GaN device research.

Ultrawide‐Bandgap Semiconductors: Research Opportunities and Challenges

“…For compound semiconductor materials, including WBG GaN and UWBG AlN, ion implantation is problematic, though there have been some recent promising reports for n-implantation of GaN coupled [329] with mixed reports for p-implantation (Mg) of GaN. [330] A major issue is that, after ion implantation, annealing of compound semiconductors requires secondnearest-neighbor (not just nearest-neighbor) re-ordering to heal the lattice damage caused by the implantation. This reordering requires relatively high annealing temperatures (relative to melting temperatures) that, at least for GaN, cause the problematic sublimation of N out of the crystal.…”

Review—Ultra-Wide-Bandgap AlGaN Power Electronic Devices

“…the ability to be doped controllably and selectively: the Si dopant becomes very deep in Al-rich AlGaN, 17 and ion implantation is difficult even in GaN. 18 Finally, Si, SiC (vertical devices), and 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". Despite these challenges, a compelling case can nonetheless be made for the investigation of UWBG materials, and in particular AlGaN, by the expected extremely strong dependence of the FOM on bandgap.…”

Mg Tilted-Angle Ion Implantation for Threshold Voltage Control and Suppression of the Short Channel Effect in GaN MISFETs

“…One recent study reported the formation of a p-type conductive layer by Mg ion implantation. Also, there are some reports of forming the p-type layer evaluated by Hall measurements [5] [6]. However, Mg ion implantation hasn't been applied to GaN device fabrication in the past.…”