Optimization of AlGaN∕GaN current aperture vertical electron transistor (CAVET) fabricated by photoelectrochemical wet etching

Abstract

AlGaN ∕ GaN current aperture vertical electron transistor (CAVET) was fabricated and optimized for band gap selective photoelectrochemical wet etching. The large polarization induced voltage offset (around 2.5–4eV) observed in the first generation CAVET was reduced to 0.7V in this structure by employing a δ Si doping layer buried 60Å below the In0.03Ga0.97N (60nm thick) and bottom GaN interface to screen the polarization fields. Other sample structures were studied to achieve an aperture with both good undercut etching and a small voltage offset. It was clearly demonstrated that etch selectivity in the GaN∕InGaN∕GaN undercut structures was influenced by hole confinement and the chemical activity of the N-face GaN.

Photoelectrochemical sidewall etching enhances light output power in GaN‐based light emitting diodes

“…1(a), the lateral etching was occurred at InGaN/GaN MQW active layer between the p-type GaN and n-type GaN layers. This lateral etching process was caused by the band-gap selective etching of InGaN material [13], and the etching rate was calculated as the value of 4.2 µm/hr. The flat and smooth GaN:Mg top surface, the triangle-shaped air holes at MQW active layer, grain-like roughening surface of n-type GaN sidewall of 10 min PEC treated LED were shown in Fig.…”

Influence of mask material and process parameters on etch angle in a chlorine-based GaN dry etch

“…There has already been a lot of research effort concerning vertical devices. [3][4][5][6][7] All of them have in common the need of a GaN dry etch step. For example, for the formation of a current-blocking layer, 6 an anisotropic etch with a high etch angle is necessary.…”

Wet chemical etching of Al 0.65 Ga 0.35 N in aqueous KOH solutions

“…The mechanism of wet etching of GaN was illustrated to be the formation of an insoluble coating of presumably gallium hydroxide (Ga(OH) 3 ) and the subsequent dissolving in different solvents 14,16,18,23 . Many methods are used to characterize the etched surface, including scanning electron microscopic (SEM) [12][13][14][16][17][18][19][20][21]23,26,27,[29][30][31] , atomic force microscopy (AFM) 8,24,27 , transmission electron microscopy (TEM) 19,21,22 , x-ray photoelectron spectroscopy (XPS) 28 , Auger electron spectroscopy (AES) 23 , energy-dispersive x-ray analysis (EDX) 18 , x-ray diffraction (XRD) 18 , and spectroscopic ellipsometry (SE) 15 . A comprehensive review for wet chemical etching of GaN, AlN, and SiC has been presented by D. Zhuang and J. H. Edgar 5 .…”

“…In addition to these dry etching methods, wet chemical etching processes have been proved to be effective techniques to avoid damages introduced in etching courses [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] . In order to achieve a suitable etch rate and smooth surface, photoelectrochemical (PEC) wet etching of GaN-based materials 14,[16][17][18][19]21,[23][24][25][26][27]29,30 , which was first demonstrated by Minsky et al 14 , has been studied extensively, especially by the groups of E. L. Hu and I. Adesida 14,16,17,19,21,25,29,30 . The mechanism of wet etching of GaN was illustrated to be the formation of an insoluble coating of presumably gallium hydroxide (Ga(OH) 3 ) and the subsequent dissolving in different solvents 14,16,18,23 .…”