Dataset for TiN Thin Films Prepared by Plasma-Enhanced Atomic Layer Deposition Using Tetrakis(dimethylamino)titanium (TDMAT) and Titanium Tetrachloride (TiCl4) Precursor

A dataset in this report is regarding an article “Ultrathin Effective TiN Protective Films Prepared by Plasma-Enhanced Atomic Layer Deposition for High Performance Metallic Bipolar Plates of Polymer Electrolyte Membrane Fuel Cells” [1]. TiN (Titanium Nitride) thin films were deposited by Plasma-Enhanced Atomic Layer Deposition (PEALD) method using well known two types of precursor: using tetrakis(dimethylamino)titanium (TDMAT) and titanium tetrachloride (TiCl4), and plasma. Summarized reports, growth characteristics (growth rate as a function of each precursor pulse time, plasma power, precursor and plasma purge time, thickness depending on the number of PEALD cycles), each precursor structural information and the atomic force micrographs (AFM) data are herein demonstrated. For TDMAT-TiN, N2 plasma was used as a reactant whereas, H2+N2 plasma was used as TiCl4-TiN reactant. To apply the bipolar plate substrate, two types of TiN thin films were introduced into Stainless steel (SUS) 316L.

Plasma-Enhanced Atomic Layer Deposition (PEALD) TiN (Titanium Nitride) tetrakis(dimethylamino)titanium (TDMAT) titanium tetrachloride (TiCl 4 ) a b s t r a c t A dataset in this report is regarding an article "Ultrathin Effective TiN Protective Films Prepared by Plasma-Enhanced Atomic Layer Deposition for High Performance Metallic Bipolar Plates of Polymer Electrolyte Membrane Fuel Cells" [1] . TiN (Titanium Nitride) thin films were deposited by Plasma-Enhanced Atomic Layer Deposition (PEALD) method using well known two types of precursor: using tetrakis(dimethylamino)titanium (TDMAT) and titanium tetrachloride (TiCl 4 ), and plasma. Summarized reports, growth characteristics (growth rate as a function of each precursor pulse time, plasma power, precursor and plasma purge time, thickness depending on the number of PEALD cycles), each precursor structural information and the atomic force micrographs (AFM) data are herein demonstrated. For TDMAT-TiN, N 2 plasma was used as a reactant whereas, H 2 + N 2 plasma was used as TiCl 4 -TiN reactant. To apply the bipolar plate substrate, two types of TiN thin films were introduced into Stainless steel (SUS) 316L.
© 2020 The Author(s Value of the data -The data is useful to understand the study conducted in "Ultrathin Effective TiN Protective Films Prepared by Plasma-Enhanced Atomic Layer Deposition for High Performance Metallic Bipolar Plates of Polymer Electrolyte Membrane Fuel Cells" -This data is helpful to researcher to select the Ti precursor according to the application purpose. -This data gives some information of deposition condition when researcher uses two kinds of the Ti precursors for ALD.

Data Description
As shown in Table 1 , thermal decomposition of TDMAT precursor is occurred over 200 °C and TDMAT-TiN was deposited at less than or equal to 200 °C. On the other hands, TiCl 4 -TiN thin films have been studied over 300 °C because TiCl 4 precursor is needed for high temperature mostly due to the problem for the incorporation of chlorine.
To confirm the self-limiting characteristics of TDMAT-TiN and TiCl 4 -TiN, the effects of growth parameters on the growth rates of TDMAT-TiN and TiCl 4 -TiN were systemically investigated. [2] Figure 1 a shows the dependence of the growth rates of the films on the N 2 plasma pulse time for TDMAT-TiN and on the N 2 /H 2 mixed plasma pulse time for TiCl 4 -TiN at a fixed precursor pulse time of 1 sec, precursor and plasma purge times of 10 sec, and a plasma power of 300 W. For a given set of conditions, the growth rates of TDMAT-TiN and TiCl 4 -TiN were saturated at 0.052 nm/cycle and 0.054 nm/cycle, which confirms that 10 sec of plasma pulse time was sufficient to completely react with the adsorbed precursors. Figure 1 b shows the growth rates  of TDMAT-TiN and TiCl 4 -TiN thin films as a function of the plasma power. In these experiments, the precursor pulse time, precursor purge time, plasma pulse time, and plasma purge time were fixed at 1 sec, 10 sec, 10 sec, and 10 sec, respectively. In the case of TDMAT-TiN, a plasma power greater than 180 W was sufficient to complete the chemical reaction with the adsorbed precursors during the plasma pulse time of 10 sec, whereas a power significantly greater than 300 W was required for TiCl 4 -TiN for the same plasma pulse time. We subsequently investigated the effect of precursor and plasma purge times to clarify the complete removal of the volatile byproducts after the precursor pulse and plasma pulse ( Figure 1 c, 1 d). For a given precursor pulse time of 1 sec and a plasma pulse time of 10 sec with a plasma power of 300 W, the results related to the saturation behavior of the growth rates demonstrated that the volatile by-products were completely removed by 10 sec of a purge pulse. Thus, we assured that the self-limiting film growth for both TDMAT-TiN and TiCl 4 -TiN was achieved by adopting a sequential exposure of 1 sec of a precursor pulse, 10 sec of a purge pulse, 10 sec of a plasma pulse with a plasma power of 300 W, and 10 sec of a plasma pulse. Because of the self-limiting growth of TDMAT-TiN and TiCl 4 -TiN, the film thickness exhibits a linear dependence on the number of PEALD cycles, as shown in Figure 1 e and 1 f, and we can digitally control the desired film thickness with the number of PEALD cycles. Table 2 shows structural information of two precursors. Projection area exhibits the lateral area occupied by one precursor molecule on the surface. Accordingly, distance of precursor perpendicular to the maximum projection can be calculated. According to the projection area and distance of precursor, TiCl 4 molecular size is smaller than TDMAT.
To quantitatively investigate the surface roughness before and after the PEALD-TiN coating of SS316L, we performed contact-mode atomic force microscopy to characterize the bare SS316L, TDMAT-TiN-coated SS316L, and TiCl 4 -TiN-coated SS316L with a scan area of 1 μm 2 , the results are shown in Figure 2 . The TiN thin films were prepared with 1050 PEALD cycles using two precursors, TDMAT and TiCl 4 , on SS316L substrates. The measured root-mean-square (RMS) surface roughness values were 3.840 nm, 2.794 nm and 3.871 nm for the bare SS316L, TMDAT-TiNcoated SS316L and TiCl4-TiN-coated SS316L, respectively.

Experimental Design, Materials, and Methods
TiN thin films were prepared by the PEALD method using two types of precursors (i.e., TD-MAT and TiCl 4 ). To measure the overall film growth rate, we also used a 250-nm-thick SiO 2 /Si substrate whereas 0.2-mm-thick stainless steel 316L (SS316L) substrates was used for applying the bipolar plate. PEALD-TiN thin films were deposited at different growth temperatures of 200 °C and 350 °C for TDMAT and TiCl 4 , respectively. One deposition cycle of TiN using TD-MAT consisted of a TDMAT precursor injection with 25 sccm Ar carrier gas, a purge pulse with 50 sccm Ar, a pulse for the N 2 plasma exposure with 100 sccm N 2 gas, and another 50 sccm Ar purge pulse. For the PEALD-TiN using TiCl 4 , the canister containing TiCl 4 was maintained at a temperature of 25 °C because of its high vapor pressure. Similarly, one deposition cycle of TiN using TiCl 4 consisted of a TiCl 4 precursor injection with 25 sccm Ar carrier gas, a purge pulse with 50 sccm Ar, a pulse for exposure to a mixed plasma with 100 sccm N 2 and 20 sccm H 2 gas, and another 50 sccm Ar purge pulse. During the PEALD-TiN processes using TDMAT and TiCl 4 , Ar gas was consistently supplied to the chamber at a flow rate of 50 sccm, and the chamber pressure was constantly maintained at 3 Torr. For the plasma pulse, radio-frequency (RF) plasma was used. More detailed experiment and condition are included in "Ultrathin Effective TiN Protective Films Prepared by Plasma-Enhanced Atomic Layer Deposition for High Performance Metallic Bipolar Plates of Polymer Electrolyte Membrane Fuel Cells".
And, the film thickness was analyzed by field-emission scanning electron microscopy (FE-SEM, Hitachi, S-4800). Film morphology on SUS 316L was investigated by MFP-3D AFM (Asylum Research). Precursor structural information was simulated by Mavin program.

Funding Information
This research was mainly supported by the Global Frontier R&D Program

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article.