In-system photoelectron spectroscopy study of tin oxide layers produced from tetrakis(dimethylamino)tin by plasma enhanced atomic layer deposition

Abstract

Tin oxide (SnO2) layers were deposited using plasma enhanced atomic layer deposition with tetrakis(dimethylamino)tin precursor and oxygen plasma. The deposited layers were analyzed by spectral ellipsometry, conductivity measurements, and in-system photoelectron spectroscopy. Within a deposition temperature range of 90–210 °C, the resistivity of the SnO2 layers decreases by 5 orders of magnitude with increasing deposition temperature. At the same time, the refractive index at 632.8 nm increases from 1.7 to 1.9. These changes in bulk layer properties are connected to results from photoelectron spectroscopy. It is found that decreasing carbon and nitrogen contaminations in the tin oxide layers lead to decreasing optical band gaps and increasing refractive index. Additionally, for the deposited SnO2 layers, a shoulder in the O 1s core level spectrum is observed that decreases with the deposition temperature and thus is proposed to be related to hydroxyl groups.

Chemical Reaction and Ion Bombardment Effects of Plasma Radicals on Optoelectrical Properties of SnO2 Thin Films via Atomic Layer Deposition

“…The XPS spectra were calibrated by C 1s (284.5 eV). The peak value of O V was located at 532 ± 0.1 eV and that of O L were located at 531 ± 0.1 eV [ 24 , 25 , 26 ]. The Sn 3d peak for the films prepared at different plasma powers are added as shown in Figure S1 .…”

“…The Sn 3d curves are deconvoluted into two components of Sn 4+ and Sn 2+ . The higher binding energy component at ~487.5 eV is attributed to the Sn 4+ , while the lower one at ~486.4 eV is typically assigned to Sn 2+ [ 24 , 25 , 26 ]. The electrical properties including the resistivity, carrier concentration, and mobility were conducted by Hall effect measurements (HMS-5000, Side Semiconductor Technology, Xiamen, China) at room temperature.…”

“…Comparable to what has been accomplished for ALD, the challenge for PEALD regards the effects of plasma radicals on the deposition mechanism and the quality of deposited SnO 2 thin films. With the development of plasma assistance for the deposition, there are an increasing number of articles about high-quality PEALD SnO 2 films [ 22 , 23 , 24 , 25 , 26 ]. On the other hand, the SnO 2 thin films have been widely used in many applications such as gas sensors [ 16 ], photovoltaics [ 19 , 20 ], and photodetectors [ 20 ].…”

“…Owing to the high reactivity, the oxygen gas (O 2 ) is one of the most used sources to generate oxygen radicals, assisting the chemical reaction in PEALD process. Accordingly, it is found that PEALD, playing a crucial role in high quality of SnO 2 thin films, is worth researching deeply because the coordination of oxygen vacancies is related to the intensity of oxygen radicals [ 24 ]. Therefore, the target of this study is to optimize the PEALD O 2 plasma power and investigate its effect on the SnO 2 thin film properties.…”

Antireflective nanotextures for monolithic perovskite-silicon tandem solar cells

“…The SnO 2 layers were deposited using plasma-enhanced atomic layer deposition and characterized with ellipsometry. 15 The data for the RF-PECVD hydrogenated amorphous silicon (a-Si:H) layers 16 were extracted using SCOUT. 17 For LiF 18 and Spiro-OMeTAD 19 we used data from literature.…”