TY - JOUR
T1 - Improved minority carrier lifetime in p-type GaN segments prepared by vacancy-guided redistribution of Mg
AU - Shima, K.
AU - Tanaka, R.
AU - Takashima, S.
AU - Ueno, K.
AU - Edo, M.
AU - Kojima, Kazunobu
AU - Uedono, A.
AU - Ishibashi, S.
AU - Chichibu, S. F.
N1 - Funding Information:
The authors thank T. Ohtomo of Tohoku University for helping the PL experiments. This work was supported in part by the NEDO-Program for Cross-ministerial Strategic Innovation Promotion, the MEXT-Program for Research and Development of Next-Generation Semiconductor to Realize Energy-Saving Society (Grant No. JPJ005357), the MEXT-Program for Creation of Innovative Core Technology for Power Electronics (Grant No. JPJ009777), the MEXT-Program of Dynamic Alliance for Open Innovation Bridging Human, Environment and Materials, JSPS KAKENHI (Grant Nos. JP16H06427 and 21H01826) by MEXT, and the Tsukuba Innovation Arena (TIA) collaborative research program “Kakehashi,” Japan.
Publisher Copyright:
© 2021 Author(s).
PY - 2021/11/1
Y1 - 2021/11/1
N2 - To accelerate the development of GaN power devices, reproducible fabrication of p-type GaN (p-GaN) segments by ion-implantation (I/I) that enables selective-area doping is preferred. In this Letter, the results of time-resolved photoluminescence (PL) and spatially resolved cathodoluminescence (CL) measurements on p-GaN fabricated by I/I are presented. The p-GaN samples of a 220-nm-deep box-shaped Mg concentration profile ([Mg] = 3 × 10 18 cm - 3) were fabricated by sequential I/I of Mg and N followed by atmospheric-pressure post-implantation annealing (PIA). During PIA, Mg redistribution was guided by N-I/I-induced vacancies. The intensities of PL peaks originating from Mg acceptors were increased by increasing the PIA temperature (Ta), indicating progressive activation of Mg and simultaneous decrease in the concentration of nonradiative recombination centers (NRCs). As a result, a record-long room-temperature PL lifetime for the near-band edge emission of Ga-polar Mg-implanted p-GaN (1.4 ps) was obtained when Ta = 1300 °C. Because the species of major vacancy-type defects in the present sample was determined as vacancy clusters comprised of few Ga-vacancies (VGa) and N-vacancies (VN) such as (VGaVN)2-3, the NRC concentration is roughly estimated at around 10 17 cm - 3 provided that (VGaVN)2-3 are major NRCs with the electron-capture-coefficient of 7 × 10 - 6 cm 3 s - 1. Cross-sectional CL linescan images revealed certain activation of Mg from the surface to the leading edge of the box-shaped [Mg] profile, while NRCs remained at the depths right below the box-shaped profile. The results support advantages of using the vacancy-guided Mg redistribution technique for controlling the activated [Mg] profile and realizing p-type Ga-polar GaN:Mg segments by I/I.
AB - To accelerate the development of GaN power devices, reproducible fabrication of p-type GaN (p-GaN) segments by ion-implantation (I/I) that enables selective-area doping is preferred. In this Letter, the results of time-resolved photoluminescence (PL) and spatially resolved cathodoluminescence (CL) measurements on p-GaN fabricated by I/I are presented. The p-GaN samples of a 220-nm-deep box-shaped Mg concentration profile ([Mg] = 3 × 10 18 cm - 3) were fabricated by sequential I/I of Mg and N followed by atmospheric-pressure post-implantation annealing (PIA). During PIA, Mg redistribution was guided by N-I/I-induced vacancies. The intensities of PL peaks originating from Mg acceptors were increased by increasing the PIA temperature (Ta), indicating progressive activation of Mg and simultaneous decrease in the concentration of nonradiative recombination centers (NRCs). As a result, a record-long room-temperature PL lifetime for the near-band edge emission of Ga-polar Mg-implanted p-GaN (1.4 ps) was obtained when Ta = 1300 °C. Because the species of major vacancy-type defects in the present sample was determined as vacancy clusters comprised of few Ga-vacancies (VGa) and N-vacancies (VN) such as (VGaVN)2-3, the NRC concentration is roughly estimated at around 10 17 cm - 3 provided that (VGaVN)2-3 are major NRCs with the electron-capture-coefficient of 7 × 10 - 6 cm 3 s - 1. Cross-sectional CL linescan images revealed certain activation of Mg from the surface to the leading edge of the box-shaped [Mg] profile, while NRCs remained at the depths right below the box-shaped profile. The results support advantages of using the vacancy-guided Mg redistribution technique for controlling the activated [Mg] profile and realizing p-type Ga-polar GaN:Mg segments by I/I.
UR - http://www.scopus.com/inward/record.url?scp=85118918281&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85118918281&partnerID=8YFLogxK
U2 - 10.1063/5.0066347
DO - 10.1063/5.0066347
M3 - Article
AN - SCOPUS:85118918281
VL - 119
JO - Applied Physics Letters
JF - Applied Physics Letters
SN - 0003-6951
IS - 18
M1 - 182106
ER -