Elucidating the role of nitrogen plasma composition in the low-temperature self-limiting growth of indium nitride thin films

Abstract

Hollow-cathode plasma-generated hydrogen radicals induce crystal phase transformation from h-InN to c-In2O3 during plasma-enhanced atomic layer deposition using trimethyl-indium and Ar/N2 plasma.

Low-Temperature As-Grown Crystalline β-Ga2O3 Films via Plasma-Enhanced Atomic Layer Deposition

“…Furthermore, the amount of thickness decay during plasma half-cycle is stronger at higher (100–200 W) rf power compared to lower values (30–50 W). We ascribe this result to the more energetic plasma species (neutral radicals and charged ions) generated at higher plasma power (100–200 W), enabling the efficient removal of surface ligand groups (−CH x ). ,, However, the rather continuous and considerable thickness gains during the remaining portion of plasma exposure stages at 100–200 W (Figure a) signal possible ligand redeposition, which particularly takes place at elevated plasma power levels. , In contrast, 30 and 50 W show fairly constant thickness values (no increase) during their respective plasma exposure periods, which possibly eliminates such a ligand redeposition process. It is also worth noting that at 100 and 200 W the thickness gain behavior extends into the purge period as well, where shortly later it stabilizes, while at 30 and 50 W we do not observe such a trend.…”

“…The scans are shown for air-exposed as-received samples without any Ar sputtering (unless specified otherwise). The sputtering processes typically result in preferential etching of the lighter element (O in the Ga 2 O 3 case), leading to the accumulation of the heavier element on the surface (metallic Ga), significantly hindering the measurement of the actual bulk film stoichiometry . As such, the carbon concentrations are relatively high around ∼30 at.…”

“…Saturation curves were accomplished by monitoring the film growth process in real-time by using in situ multiwavelength ellipsometry (MWE) (FS-1, Film Sense, LLC, Lincoln, NE). Details on in situ ellipsometric data acquisition and analysis can be found in our previously published reports. ,, After achieving self-limiting ALD conditions, thicker (300-cycle) films were grown at substrate temperatures of 150, 200, and 240 °C with a fixed plasma exposure time of 10 s, 30 ms TEG pulse time, and 10 s purge times for further ex situ materials characterization. Additionally, each unit AB-type ALD cycle was followed by an in situ Ar plasma annealing treatment, which consisted of Ar plasma exposure for 20 s scanned over 50–300 W rf power.…”

On the dynamics in chemical vapor deposition of InN

“…37,38 An ALD process needs to be done at relative low temperature to ensure the stability of the chemisorbed monolayer, and therefore need sufficiently long purge time to eliminate unwanted chemical reactions of physiosorbed molecules. As our ALD work presented above was done in a temperature range higher than the typical InN ALD window of 150-300 °C , 21,22,[38][39][40][41] and considering the difference in film deposition at different temperatures observed in Figs. 1 and 2, and the thermal stability of TMI, our ALD of InN is likely to involve several In-species.…”

Recent Advances in Hollow Cathode Technology for Plasma-Enhanced ALD—Plasma Surface Modifications for Aluminum and Stainless-Steel Cathodes

“…GaN (PE-ALD) [1,8,10,11,13,14,16,20,21,30,35] GaN devices (PE-ALD) [2,4,10,11,17] Nanofibers (PE-ALD) [5,[9][10][11]] Nanostructures (ALD) [18,21] AlGaN (PE-ALD) [1,3] AlN (PE-ALD) [1,5,[19][20][21]29,32] BN (PE-ALD) [5,6,11] InN (PE-ALD) [10,11,15,[19][20][21]33,34] BInN and BGaN (PE-ALD)…”