Incorporation of Magnesium into GaN Regulated by Intentionally Large Amounts of Hydrogen during Growth by MOCVD

Abstract

Herein, metal–organic chemical vapor deposition (MOCVD) of GaN layers doped with Mg atoms to the recognized optimum level of [Mg] ≈2 × 1019 cm−3 is performed. In a sequence of MOCVD runs, operational conditions, including temperature and flow rate of precursors, are maintained except for intentionally larger flows of hydrogen carrier gas fed into the reactor. By employing the largest hydrogen flow of 25 slm in this study, the performance of the as‐grown Mg‐doped GaN layers is certified by a room‐temperature hole concentration of p ≈2 × 1017 cm−3 in the absence of any thermal activation treatment. Experimental evidence is delivered that the large amounts of hydrogen during the MOCVD growth can regulate the incorporation of the Mg atoms into GaN in a significant way so that MgH complex can coexist with a dominant and evidently electrically active isolated MgGa acceptor.

Study of Magnesium Activation Effect on Pinch-Off Voltage of Normally-Off p-GaN HEMTs for Power Applications

“…Once set all the main device parameters, two Design of Experiments (DoEs) regarding the Mg concentration have been evaluated. Simulations were run by defining the substitutional portion of the nominal Mg concentration (i.e., the electrically-active one), as an acceptor dopant in GaN with an activation energy of about 170 meV [18,19].…”