Characterization of an Mg‐implanted GaN p–i–n diode

Abstract

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.

Annealing Behavior of Vacancy‐Type Defects in Mg‐ and H‐Implanted GaN Studied Using Monoenergetic Positron Beams

“…Although techniques for activating implanted acceptors seem to not be mature, successful fabrication of the devices has started to appear recently. Greenlee et al reported the fabrication of a p‐i‐n diode by Mg implantation. The annealing process used in their experiment was a multi‐step annealing involving annealing at 1000 °C at 24 bar overpressures of N 2 and rapid thermal heating done 20 times at 1340 °C.…”

Carrier Trapping by Vacancy‐Type Defects in Mg‐Implanted GaN Studied Using Monoenergetic Positron Beams

“…The activation of implanted Mg is difficult . In the fabrication of p ‐type GaN using ion implantation, nitrogen vacancies ( V N ) are expected to act as shallow compensating centers .…”

“…The activation of implanted Mg is difficult. [10][11][12][13][14][15][16][17][18] In the fabrication of p-type GaN using ion implantation, nitrogen vacancies (V N ) are expected to act as shallow compensating centers. [19] However, since a variety of defects are introduced during ion implantation, the study of interactions between irradiation-induced defects, such as vacancy complexes between Ga vacancies (V Ga ) and V N , is important to effectively utilize ion implantation for GaN devices.…”

Detection of deep-level defects and reduced carrier concentration in Mg-ion-implanted GaN before high-temperature annealing

“…The high defect density in GaN grown on a sapphire substrate might have been a reason for the unsuccessful formation of a p-type region. Very recently, the successful formation of p-type regions on GaN epitaxial layers on free-standing GaN substrates by Mg ion implantation has been confirmed by observing the rectifying characteristics of p-n junctions formed by applying multicycle rapid thermal annealing, 5,6 standard high-temperature annealing, 7,8 and coimplantation of the N-face of GaN with Mg and H ions. 9 However, it has been reported that defects remain in the Mg-implanted GaN layer even after high-temperature annealing on the basis of positron annihilation spectroscopy (PAS) and photoluminescence (PL) studies.…”