Magnetized inductively coupled plasma etching of GaN in Cl2/BCl3 plasmas

Abstract

Articles you may be interested inComparative study of GaN mesa etch characteristics in Cl2 based inductively coupled plasma with Ar and BCl3 as additive gases J. Vac. Sci. Technol. A 32, 031301 (2014); 10.1116/1.4868616 Fabrication of ZnO photonic crystals by nanosphere lithography using inductively coupled-plasma reactive ion etching with CH 4 / H 2 / Ar plasma on the ZnO/GaN heterojunction light emitting diodes J. Vac. Sci. Technol. A 28, 745 (2010); 10.1116/1.3357282Thinning of N-face GaN ( 000 1 ¯ ) samples by inductively coupled plasma etching and chemomechanical polishing J.In this study, Cl 2 /BCl 3 magnetized inductively coupled plasmas were used to etch GaN, and the effects of magnetic confinements of inductively coupled plasmas on the GaN etch characteristics were investigated as a function of Cl 2 /BCl 3 . Also, the effects of Kr addition to the magnetized Cl 2 /BCl 3 plasmas on the GaN etch rates were investigated. The characteristics of the plasmas were estimated using a Langmuir probe and quadrupole mass spectrometry ͑QMS͒. Etched GaN profiles were observed using scanning electron microscopy. The small addition of BCl 3 ͑10%-20%͒ in Cl 2 increased the GaN etch rates for plasmas both with and without magnetic confinements. The application of magnetic confinements to the Cl 2 /BCl 3 inductively coupled plasmas increased the GaN etch rates and changed the Cl 2 /BCl 3 gas composition of the peak GaN etch rate from 10% BCl 3 to 20% BCl 3 . It also increased the etch selectivity over the photoresist, while slightly reducing the selectivity over SiO 2 . The application of the magnetic field significantly increased positive BCl 2 ϩ measured by QMS and total ion saturation current measured by the Langmuir probe. Other species such as Cl, BCl, and Cl ϩ increased, whereas species such as BCl 2 and BCl 3 decreased with the application of the magnetic field. Therefore, it appears that the increase of the GaN etch rate in our experiment is related to the increased dissociative ionization of BCl 3 by the application of the magnetic field. The addition of 10% Kr in an optimized Cl 2 /BCl 3 condition ͑80% Cl 2 /20% BCl 3 ) with the magnets increased the GaN etch rate about 60%. A more anisotropic GaN etch profile was obtained with the application of the magnetic field, and a vertical GaN etch profile was obtained with the addition of 10% Kr in an optimized Cl 2 /BCl 3 condition with the magnets.

Optimization of Mesa Etch for a Quasi-Vertical GaN Schottky Barrier Diode (SBD) by Inductively Coupled Plasma (ICP) and Device Characteristics

“…The etching selectivity of GaN over SiO 2 was significantly reduced from 10.5 to 4 as the BCl 3 concentration increased (as shown in Figure 10b). This is attributed to the positive BCl 2 + ion density increasing as the BCl 3 concentration increases, leading to an increase in the SiO 2 mask etching rate by the formation of BCl x O y in the SiO 2 [37,38]. As shown in Figure 10c, the etching rates of the microtrench slightly increased with the BCl 3 concentration up to 9%, then decreased further at 33% BCl 3 and finally vanished at 39% in both the X and Y directions.…”

A Selective Etching Route for Large-Scale Fabrication of β-Ga2O3 Micro-/Nanotube Arrays

“…For GaN, the Cl radicals in the Cl 2 plasma are the main chemical reactant, which can chemically react with GaN to obtain the volatile etch product GaCl 3 . BCl 3 can act as a wetting agent, and the BCl +3 ions and BCl +2 ions are mainly used to remove GaCl 3 by physical sputtering [32,33]. However, for Ga 2 O 3 , BCl 3 plasma exhibits a stronger etching effect, and Cl 2 plasma exhibits a weaker etching effect [21].…”

Ultrahigh GaN:SiO2etch selectivity byin situsurface modification of SiO2in a Cl2-Ar plasma

“…Based on the values in the NIST-JANAF Thermochemical Tables, both reactions the formation of Al x O y compounds on the AlGaN surface [33][34][35][36]. Thus, the reaction of Al or AlCl with the SiO 2 surface is expected reduce the mask etch rate, and therefore increases the GaN:SiO 2 selectivity.…”