Recent advances in the field of two-dimensional (2D) transition metal dichalcogenide (TMD) materials have indicated that atomic layer deposition (ALD) of the metal oxide and subsequent sulfidation ...could offer a method for the synthesis of large area two-dimensional materials such as MoS2 with excellent layer control over the entire substrate. However, growing large area oxide films by ALD with sub 1 nm nucleation coalescence remains a significant challenge, and the necessary steps are unexplored. In this work, we demonstrate the necessary process improvements required to achieve sub 1 nm nucleation control by characterization of nucleation domains formed by oxide deposition. Synthesis of the TMD MoS2 from sulfidation of oxide deposited by both thermal ALD from (tBuN)2(NMe2)2Mo and O3 and plasma enhanced ALD (PEALD) from (tBuN)2(NMe2)2Mo and remote O2 plasma was performed. Large uniform MoS2 areas were achieved by optimizing the effects of various growth process conditions and surface treatments on the ALD nucleation and growth of Mo-oxide and the postsulfidation of MoS2. In addition to insights into the control of the oxide deposition, film chemistry analysis during a multistep sulfidation based on less toxic sulfur as compared to H2S was performed for several temperature profiles revealing sulfur incorporation and molybdenum reduction at low temperatures but higher temperatures required for 2H crystal structure formation. The knowledge gained of the ALD, PEALD, and postsulfidation was leveraged to demonstrate tunable film thickness and centimeter-scale monolayer growth. Material quality can be studied independently of the MoS2 layer count as demonstrated by the control of the monolayer photoluminescence intensity by the temperature ramp rate during sulfidation.
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IJS, KILJ, NUK, PNG, UL, UM
Small signal Surface Photo-voltage (SPV) measurement techniques have been applied to monitor ion implants typical of those used for layer-transfer SOI processes. This SPV wafer mapping technique was ...investigated for sensitivity to dose, implant uniformity, and repeatability for hydrogen and helium implants into (100) silicon wafers through a 1450Aå surface oxide. A normalized sensitivity of approximately 1.2 for the investigated cases was observed. A demonstrated repeatability of less than 0.5% 1-sigma standard deviation was measured for a multi-day period on hydrogen implanted wafers. The small signal SPV metrology technique presented allows in-line SPC control of the critical ion implant step within the SOI wafer manufacturing process.
The demonstrated benefits provided by Atomic Layer Deposition (ALD) in producing films of exceptional uniformity, and conformality, has set the stage for its use in large area, and batch processing ...applications. Two key elements which drive the adoption of ALD for these applications are the ability to scale the film processes from small to large size substrates, and for the effective throughput to be increased in a manner consistent with volume production needs. In this paper we discuss the results of scaling processes from small format substrates to large format substrates, along with a presentation of the parameters which influence throughput. Additionally we describe the basic underpinnings of batch and roll-to-roll ALD systems, and the design factors which must be considered when used in a high volume setting.
The effects of `fast' ramp-rates (up to 425 degree C/s) and spike anneals are investigated for 0.25 keV, 0.5 keV, and 1.0 keV super(11)B+ and for 1.1 and 2.2 keV BF sub(2) at a dose of 1e15/cm ...super(2). Below an implant energy threshold where no extended defects form, fast ramp-rates become important in minimizing the thermal diffusion component and reducing the junction depth. Above this implant energy threshold, TED minimizes the advantages of these fast ramp-rates. Annealing in a low and controlled O sub(2) ppm in N sub(2) ambient further reduces diffusion by minimizing/eliminating oxygen related enhanced diffusion effects, while simultaneously optimizing anneal reproducibility and across-the-wafer uniformity.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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