Magnesium/nitrogen and beryllium/nitrogen coimplantation into GaN

Abstract

The nitrogen coimplantation characteristics in the Mg- and Be-implanted GaN with different dopant concentration ratios have been systematically investigated. The Hall-effect measurements show that the p-type characteristics are produced in the Mg- and Be-implanted GaN by the coimplantation of N atoms and subsequent annealing, which is essentially related to the column II/V dopant concentration ratio and annealing condition. This behavior may be attributed to the reduction of self-compensation induced by N vacancies and the enhanced acceptor substitution, which is in reasonable agreement with the surface stoichiometric switching determined by x-ray photoelectron spectroscopy measurements. From photoluminescence data, the activation energy of the Be acceptor level is evaluated to be about 145meV, which is shallower than that of the Mg acceptor. These experimental results indicate that the selective-area N coimplantation with Mg and Be atoms into GaN is an effective method to enhance the p-type conductivity and to improve the p-type Ohmic contact resistance.

Multicycle rapid thermal annealing technique and its application for the electrical activation of Mg implanted in GaN

“…This makes high pressure annealing too expensive for industry and difficult to scale up to lager wafer sizes. RTA is attractive for GaN annealing in terms of achievable temperatures and costs, but it has not been shown that RTA enables electrical activation of Mg after the implantation in GaN without co-doping with other ions [9]. One probable reason for these unsuccessful attempts of using RTA to activate the implanted Mg is the short duration of the GaN annealing at high temperatures.…”

Vacancy‐type defects and their annealing behaviors in Mg‐implanted GaN studied by a monoenergetic positron beam

“…It has been reported that the activation of implanted impurities in GaN is difficult compared with that of typical semiconductors . For acceptor‐impurity implantation, nitrogen vacancies ( V N s) are expected to be introduced, and they act as shallow compensating centers.…”

Extremely Slow Decay of Yellow Luminescence in Be‐Doped GaN and Its Identification

“…The activation energy of substitutional Be acceptors is still under debate. Some groups found activation energies between 90 and 150 meV, while others report values between 170 and 250 meV . Lany et al found in their calculations two acceptor states of Be in GaN: a deep localized ground state at around VBM + 0.45 eV, and a shallow effective‐mass‐like delocalized state at around VBM + 0.15 eV .…”