We report a new thermal atomic layer deposition (thermal-ALD) process including an air exposure as a third precursor to deposit crystalline TiO2 anatase thin films from tetrakis(dimethylamido)titanium(IV) (TDMAT) and water at deposition temperatures as low as 180 °C and film thicknesses as low as 10 nm. This ALD process enables TiO2-antase crystal growth during the deposition at low temperatures (< 220 °C). This additional oxidant pulse is used to fully oxidize the Ti to a 4+ state in the amorphous film, lowering the barrier to crystalline anatase formation. This new approach is informed by preliminary studies of post-deposition annealing (PDA) of thermal ALD films in both nitrogen and air atmospheres, which demonstrate the importance of having an oxidizing atmosphere to achieve the nucleation of the crystalline anatase phase. This oxidizing atmosphere is subsequently introduced into the ALD cycle as a third precursor and is shown to be more effective and efficient in promoting the crystalline transformation than even by post-deposition annealing. The crystalline anatase phase is verified by Raman spectroscopy and grazing incidence X-ray diffraction (GIXRD). The mechanism for crystallization during the TDMAT/H2O/air ALD cycle is probed by chemical state analysis via X-ray photoelectron spectroscopy (XPS). We propose that sub-oxidation in TiO2 thin films deposited by the thermal-ALD process inhibits crystallization during ALD from TDMAT/H2O chemistry. Scanning electron microscopy (SEM) is used to investigate the microstructure of these TiO2 thin films as a function of thickness (5 nm to 50 nm) and deposition temperature (180 °C to 220 °C). The reported layer-by-layer air anneal process is found to crystallize entire films in shorter total process times than thermal-ALD with ex situ post deposition annealing at identical temperatures, presumably due to the improved surface diffusion kinetics accessed during the deposition process.
{"title":"Crystalline as-deposited TiO 2 anatase thin films grown from TDMAT and water using thermal atomic layer deposition with in situ layer-by-layer air annealing","authors":"Jamie P. Wooding, K. Kalaitzidou, M. Losego","doi":"10.3897/aldj.2.117753","DOIUrl":"https://doi.org/10.3897/aldj.2.117753","url":null,"abstract":"We report a new thermal atomic layer deposition (thermal-ALD) process including an air exposure as a third precursor to deposit crystalline TiO2 anatase thin films from tetrakis(dimethylamido)titanium(IV) (TDMAT) and water at deposition temperatures as low as 180 °C and film thicknesses as low as 10 nm. This ALD process enables TiO2-antase crystal growth during the deposition at low temperatures (< 220 °C). This additional oxidant pulse is used to fully oxidize the Ti to a 4+ state in the amorphous film, lowering the barrier to crystalline anatase formation. This new approach is informed by preliminary studies of post-deposition annealing (PDA) of thermal ALD films in both nitrogen and air atmospheres, which demonstrate the importance of having an oxidizing atmosphere to achieve the nucleation of the crystalline anatase phase. This oxidizing atmosphere is subsequently introduced into the ALD cycle as a third precursor and is shown to be more effective and efficient in promoting the crystalline transformation than even by post-deposition annealing. The crystalline anatase phase is verified by Raman spectroscopy and grazing incidence X-ray diffraction (GIXRD). The mechanism for crystallization during the TDMAT/H2O/air ALD cycle is probed by chemical state analysis via X-ray photoelectron spectroscopy (XPS). We propose that sub-oxidation in TiO2 thin films deposited by the thermal-ALD process inhibits crystallization during ALD from TDMAT/H2O chemistry. Scanning electron microscopy (SEM) is used to investigate the microstructure of these TiO2 thin films as a function of thickness (5 nm to 50 nm) and deposition temperature (180 °C to 220 °C). The reported layer-by-layer air anneal process is found to crystallize entire films in shorter total process times than thermal-ALD with ex situ post deposition annealing at identical temperatures, presumably due to the improved surface diffusion kinetics accessed during the deposition process.","PeriodicalId":475959,"journal":{"name":"Atomic Layer Deposition","volume":"6 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141267087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Atmospheric-pressure plasma-enhanced spatial atomic layer deposition (PE-spatial-ALD) of SiN x is demonstrated for the first time. Using bis(diethylamino)silane (BDEAS) and N 2 plasma from a dielectric barrier discharge source, a process was developed at low deposition temperatures (≤ 250 °C). The effect of N 2 plasma exposure time and overall cycle time on layer composition was investigated. In particular, the oxygen content was found to decrease with decreasing both above-mentioned parameters. As measured by depth profile X-ray photoelectron spectroscopy, 4.7 at.% was the lowest oxygen content obtained, whilst 13.7 at.% carbon was still present at a deposition temperature of 200 °C. At the same time, deposition rates up to 1.5 nm/min were obtained, approaching those of plasma enhanced chemical vapor deposition and thus opening new opportunities for high-throughput atomic-level processing of nitride materials.
{"title":"Atmospheric-pressure plasma-enhanced spatial atomic layer deposition of silicon nitride at low temperature","authors":"Jie Shen, Fred Roozeboom, Alfredo Mameli","doi":"10.3897/aldj.1.101651","DOIUrl":"https://doi.org/10.3897/aldj.1.101651","url":null,"abstract":"Atmospheric-pressure plasma-enhanced spatial atomic layer deposition (PE-spatial-ALD) of SiN x is demonstrated for the first time. Using bis(diethylamino)silane (BDEAS) and N 2 plasma from a dielectric barrier discharge source, a process was developed at low deposition temperatures (≤ 250 °C). The effect of N 2 plasma exposure time and overall cycle time on layer composition was investigated. In particular, the oxygen content was found to decrease with decreasing both above-mentioned parameters. As measured by depth profile X-ray photoelectron spectroscopy, 4.7 at.% was the lowest oxygen content obtained, whilst 13.7 at.% carbon was still present at a deposition temperature of 200 °C. At the same time, deposition rates up to 1.5 nm/min were obtained, approaching those of plasma enhanced chemical vapor deposition and thus opening new opportunities for high-throughput atomic-level processing of nitride materials.","PeriodicalId":475959,"journal":{"name":"Atomic Layer Deposition","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135822351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：