| Autor: |
Narita, Tetsuo, Yoshida, Hikaru, Tomita, Kazuyoshi, Kataoka, Keita, Sakurai, Hideki, Horita, Masahiro, Bockowski, Michal, Ikarashi, Nobuyuki, Suda, Jun, Kachi, Tetsu, Tokuda, Yutaka |
| Předmět: |
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| Zdroj: |
Journal of Applied Physics; 9/7/2020, Vol. 128 Issue 9, p1-13, 13p |
| Abstrakt: |
The fabrication processes of p-type regions for vertical GaN power devices are investigated. A p-type body layer in a trench gate metal-oxide-semiconductor field-effect transistor requires precise control of the effective acceptor concentration, which is equal to the difference between the Mg acceptor concentration (Na) and the compensating donor concentration (Nd). The carbon atoms incorporated during growth via metalorganic vapor phase epitaxy substitute nitrogen sites (CN) and function as donor sources in a p-type GaN layer. Since interstitial H atoms (H i) also compensate holes, their removal from an Mg-doped layer is crucial. Extended anneals to release H atoms cause the formation of extra hole traps. The p+ capping layer allows effective and rapid removal of H atoms from a p-type body layer owing to the electric field across the p+/p– junction. On the other hand, selective area p-type doping via Mg ion implantation is needed to control the electrical field distribution at the device edge. Ultrahigh-pressure annealing (UHPA) under a nitrogen pressure of 1 GPa enables post-implantation annealing up to 1753 K without thermal decomposition. Cathodoluminescence spectra and Hall-effect measurements suggest that the acceptor activation ratio improves dramatically by annealing above 1673 K as compared to annealing at up to 1573 K. High-temperature UHPA also induces Mg atom diffusion. We demonstrate that vacancy diffusion and the introduction of H atoms from the UHPA ambient play a key role in the redistribution of Mg atoms. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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