Selective area doping of GaN toward high-power applications

Abstract

Selective area doping in GaN, especially p-type, is a critical and inevitable building block for 
the realization of advanced device structures for high-power applications, including, but not 
limited to, current-aperture vertical electron transistors (CAVETs), junction termination 
extensions (JTEs), junction barrier Schottky (JBS) diodes, junction field-effect transistors 
(JFETs), vertical-channel junction FETs (VC-JFETs), U-shaped metal–oxide–semiconductor 
field-effect transistors (U-MOSFETs), and Fin MOSFETs. This paper reviews and 
summarizes some of the recent advances in the fields of selective area etching and regrowth, 
ion implantation, and polarity-dependent doping that may lead to the practical realization of 
GaN-based power devices.

Vacancy‐Type Defects and Their Trapping/Detrapping of Charge Carriers in Ion‐Implanted GaN Studied by Positron Annihilation

“…[19] It is well known that activation of Mg implanted into GaN is more difficult than that of Si or Ge. [7,20] This has been associated with the presence of donor-like point defects such as nitrogen vacancies (V N ) because they act as compensators. In this context, additional implantation of N or F atoms into Mg-implanted GaN is considered to be effective to enhance the activation rate of implanted Mg. [15,21] The sequential implantation of N was reported to be also effective to suppress the diffusion of Mg during postimplantation annealing.…”

“…However, even using such layers, the highest annealing temperature is limited to be around 1300 °C. [7,20] Several annealing techniques have been applied to decrease thermal budgets, such as microwave annealing, rapid thermal annealing (RTA), multicycle RTA, laser annealing, etc. [23][24][25][26] A rather straightforward approach to suppress the degradation of GaN during annealing is ultrahigh-pressure annealing (UHPA).…”