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Ion implantation of magnesium for p‐type GaN presents many opportunities; however, activation has proven difficult due to the decomposition of GaN at relevant annealing temperatures. Herein, testing the efficacy of multiple in situ and ex situ caps based on aluminum nitride and silicon nitride for GaN protection during annealing is presented. Photoluminescence shows better activation for in situ metal organic chemical vapor deposition (MOCVD)‐grown aluminum nitride caps compared with ex situ sputtered aluminum nitride and the best performance by ex situ plasma‐enhanced chemical vapor deposition (PECVD) silicon nitride. Furthermore, only samples annealed at the highest temperatures tested show preferential growth of UV luminescence to yellow‐green luminescence reinforcing the need for better capping solutions and higher temperature annealing. [ABSTRACT FROM AUTHOR]

An Mg-implanted p-i-n diode was fabricated and characterized. Mg activation was achieved using the multicycle rapid thermal annealing technique with rapid heating pulses up to 1340 °C. The surface of the implanted GaN after annealing was smooth (0.94 nm RMS roughness) with growth steps evident as characterized by atomic force microscopy. The full width at half-maximum of the implanted GaN E2 Raman mode approaches that of the as-grown GaN after the annealing process, indicating that the annealing process is able to reverse most of the implantation damage. The Mg-implanted p-i-n diode exhibits rectification and a low leakage current of 0.11 μA cm−2 at a bias of −10 V. Under forward bias, light emission was observed from the p-i-n diode. The implantation and activation of Mg in a GaN-based device, demonstrated for the first time in this research, is a key enabling step for future optoelectronic and power electronic devices. Current-voltage characteristics of the Mg-implanted p-i-n diode with an inset of the device schematic. [ABSTRACT FROM AUTHOR]

Activation of ion‐implanted p‐type dopants in gallium nitride has demonstrated great progress utilizing high pressures to enable novel and traditional device architectures; however, such conditions consistently exhibit anomalously enhanced diffusion up to several microns in very short periods of time for device relevant concentrations. Here, this diffusion is shown to be modulated by unintentional hydrogen content within the anneal ambient and thus controllable by inclusion of a high‐temperature hydrogen getter. Furthermore, diffusion is also shown to be greatly suppressed using co‐implanted oxygen at low concentrations while simultaneously maintaining characteristics of p‐type material in photoluminescence. Subsequently, after annealing at 1300 °C for 30 min in 3.8 kbar of nitrogen pressure, the magnesium concentration in the diffusion tail is suppressed by 28% at 1–1.5 μm in depth using a hydrogen getter alone, which reduces hydrogen uptake by 45% and fully suppressed at >1 μm in depth using co‐implantation alone and further reduced with concurrent use of a hydrogen getter. Co‐implantation alone reduces the in‐diffused magnesium dose by 60% compared to reference samples. [ABSTRACT FROM AUTHOR]

Optical, electrical, and mass spectrometry experiments were carried out on solution grown GaN crystals to detect and identify the impurities incorporated in faces of different polarity at different growth condition. Selective etching, photoluminescence and cathodoluminescence imaging indicate that Mg acceptors incorporate preferentially in GaN nitrogen polar face. Larger incorporation of Mg was observed on crystals grown at lower temperatures. Capacitance–voltage measurements verified p-type conductivity due to an excess of Mg acceptors on N-polar face of the GaN crystals. These results suggest that epitaxial layers deposited from liquid phase may be the best approach to produce p-type conducting layers with high hole concentration and low defect density. [ABSTRACT FROM AUTHOR]