Positron annihilation and cathodoluminescence study on inductively coupled plasma etched GaN

Abstract

Etching damage induced by inductively coupled plasma (ICP) with a mixture of Cl2 and BCl3 gases and the effect of subsequent annealing in N2were studied through positron annihilation and cathodoluminescence (CL) for Mg‐doped and Si‐doped GaN. The changes in the concentration of nonradiative defects and in the shape of band bending caused by ICP etching or subsequent annealing were studied by comparing the CL intensities and the diffusion lengths of implanted positrons, respectively. For Mg‐doped GaN, CL spectra revealed that etching inactivated the Mg acceptors at the near‐surface region. After annealing at 900 °C, the Mg acceptors were reactivated. For Si‐doped GaN, etching introduced neutral vacancy‐type defects, and after annealing at 900 °C, the etching‐induced defects almost disappeared. However, there were residual nonradiative defects on the top surface that were associated with a change in the surface's Fermi level position.

Cathodoluminescence Study on Thermal Recovery Process of Mg‐Ion Implanted N‐Polar GaN

“…Kojima et al performed the photoluminescence study on Mg‐ion implanted GaN layers with 500‐nm‐depth box profile of concentration from 10 17 to 10 19 cm −3 and showed that high‐annealing temperature was effective in decreasing non‐radiative recombination centers (NRCs) . Such an optical measurement is utilized as a tool to investigate the dependence of process damage on its conditions, owing to the high sensitivity to defects in GaN …”

“…[10] Such an optical measurement is utilized as a tool to investigate the dependence of process damage on its conditions, owing to the high sensitivity to defects in GaN. [11,12] In this paper, using the cathodoluminescence (CL) analysis, we characterized the Mg-and H-ions implanted diodes of Npolar GaN(000 1) exhibiting superior rectification, and then investigated the influence of the temperature and the duration in post-implantation annealing for samples with the different implantation depth using different implant energies in order to further improve the crystalline quality.…”

Reduction of plasma-induced damage in n-type GaN by multistep-bias etching in inductively coupled plasma reactive ion etching

“…many reports that the characteristics of etched-GaN samples can be recovered by the adoption of a subsequent annealing process. [29][30][31] The annealing temperatures used in these reports were from 600 °C to 900 °C. Relatively high temperatures have thus been used in attempts to recover from etching damage.…”

Selective area doping of GaN toward high-power applications

“…Dry etching has been successfully implemented with plasma techniques: magnetron reactive ion etching (RIE) [7,8], ion beam etching [9][10][11], plasma etching [12][13][14], electron cyclotron resonance etching [15][16][17], RIE [18,19], inductively coupled plasma (ICP) [20,21], and ICP-RIE [22,23]. All of these may cause plasma-induced damage (PID) [24][25][26][27][28] to and contamination of the material under treatment [29].…”