Excess Carrier Lifetime Measurement for Plasma-Etched GaN by the Microwave Photoconductivity Decay Method

We measured the excess carrier lifetimes in GaN by the microwave photoconductivity decay (µ-PCD) method. We characterized undoped GaN, Si-doped n-GaN, and Mg-doped p-GaN before and after etching using inductively coupled plasma (ICP). For all the samples, decay curves had both fast and slow components, and carrier lifetimes for the p-GaN were significantly shorter than those for the other samples. For the undoped GaN, ICP etching enhanced the slow component compared with the as-grown sample. This would be due to generation of hole traps by ICP etching.