Hollow cathode plasma-assisted atomic layer deposition of crystalline AlN, GaN and Al_xGa_1−xN thin films at low temperatures

Abstract

The authors report on the use of hollow cathode plasma for low-temperature plasma-assisted atomic layer deposition (PA-ALD) of crystalline AlN, GaN and AlxGa1−xN thin films with low impurity concentrations.

Substrate temperature influence on the properties of GaN thin films grown by hollow-cathode plasma-assisted atomic layer deposition

“…Figure 2 shows the C can also be similarly decomposed into two components at 396.37 and 394.57 eV, which is assigned to the N-Ga bond and Auger Ga peaks. 12 Although the spectral locations and intensities of Ga 3d and N 1s peaks were found to be slightly different for GaN samples grown at 450 C, the atomic composition of GaN film was hardly changed. The HR-XPS spectrum of Ga 3d [ Fig.…”

“…2(c)] for GaN film grown at 450 C was fitted by two subpeaks located at 20.10 and 19.15 eV, corresponding to Ga-N bonds. 12 The N 1s spectrum [ Fig. 2(d)] obtained for GaN grown at 450 C was fitted similarly using two subpeaks located at 397.49 and 395.67 eV, corresponding to N-Ga and Auger Ga bonds, respectively.…”

“…11 There are only a few recent reports on the growth of GaN films using atomic layer deposition at low temperatures (<300 C) with improved crystalline quality and electrical properties. 6,12,13 In these reports, PA-ALD of GaN using trimethylgallium, 12 triethylgallium (TEG), 6,13 and N 2 /H 2 plasma as the precursors were reported at relatively low substrate temperatures. However, yet there is no report on the effect of the substrate temperature on the structural and optical properties of GaN films grown by using hollow-cathode plasma-assisted atomic layer deposition (HCPA-ALD).…”

Low‐temperature hollow cathode plasma‐assisted atomic layer deposition of crystalline III‐nitride thin films and nanostructures

“…3 Results and discussion 3.1 AlN, GaN and Al x Ga 1-x N thin films and nanostructures In a recent study, we demonstrated the HCPA-ALD of crystalline AlN, GaN and Al x Ga 1-x N thin films at low temperature (i.e., 200 °C) using trimethylmetal precursors and NH 3 or N 2 /H 2 plasma [14]. Depositions carried out using non-optimized parameters resulted in AlN and GaN films with wafer-level non-uniformities < ±1.5%.…”

“…Recently, we showed that ALD-grown III-nitride thin films may suffer from plasma-related oxygen contamination depending on the choice of N-containing plasma gas (N 2 , N 2 /H 2 or NH 3 ) [12,13]. Therefore, as an attempt to grow O-free III-nitride thin films, we integrated an all stainless steel hollow cathode plasma (HCP) source to the ALD system, and thereby demonstrated the hollow cathode PA-ALD (HCPA-ALD) of wurtzite AIN, GaN and Al x Ga 1-x N thin films with low impurity concentrations at 200 °C [14]. GaN had not been deposited in a self-limiting fashion at such low temperatures since Sumakeris et al [15] reported the growth of GaN using a novel reactor design employing hot filaments to decompose NH 3 in 1993.…”