Session QW1: Plasma Deposition II

Live

The scaling of transistor is still on the road only thanks to the introduction of complex multiple patterning steps that are more and more expensive and time consuming. Therefore, microelectronic industry needs new solutions and integration schemes, one of them being the development of a new bottom-up approach called Area Selective Deposition (ASD) [1]. Atomic Layer Deposition (ALD) is a viable tool for nanoscale ASD by using different strategies: inherent selectivity of the precursor, surface activation, surface deactivation, and super-cycles [2]. In our lab, we developed plasma-based area selective deposition processes by merging two plasma processes in a unique ALD tool: PEALD process and Plasma etching process. In this way, super-cycles are created with alternate deposition and etching steps [3-5]. Right now, we have developed ASD processes with many different plasma-etching steps: radical only plasma etching steps, reactive ion etching steps, atomic layer etching (ALE) steps, physical only etching steps. Ions from the plasma are also used during the ALD step to spatially modify the material (density, crystallinity\textellipsis ) on 3D structures for a Topographically Selective Deposition (TSD) [6]. This presentation will outline and provide several examples of all the different scenarios developed and obtained the last years in our group as well as state of the art of other groups in the world. [1] R. Clark et al, APL Mater. 6, 058203 (2018) [2] A.J.M. Mackus et al, Chem. Mater. 31, 2 (2019) [3] R. Vallat et al, J. Vac. Sci. Technol. A 35, 01B104 (2017) [4] R. Vallat et al, J. Vac. Sci Technol. A 37, 020918 (2019) [4] A. Chaker et al, Appl. Phys. Lett. 114, 043101 (2019) [5] C. Vall\'{e}e et al, J. Vac. Sci Technol. A 38, 033007 (2020) All the following researchers have collaborated to this work. From LTM: M. Bonvalot, T. Yeghoyan, R. Vallat, A. Chaker, V. Pesce, M. Jaffal, S. Belahcen, O. Salicio, B. Pelissier, G. Lef\`{e}vre and A. Bsiesy. From CEA/LETI: R. Gassiloud and N. Poss\'{e}m\'{e}.   

Live

\newline Doping of diamond with nitrogen is of interest for various applications, including those exploiting the NV centre. NV centres in diamond can be introduced in various ways. One method is to dope the diamond film during the Microwave Plasma CVD growth process. Production of thin diamond films doped with NV- centres has the potential to be a key enabling technology for high-precision magnetic field sensing. In this talk, recent results on the growth of N-doped thin diamond films using Microwave Plasma CVD [1,2] will be discussed, and correlations between the modelled plasma parameters and the N-doped diamond film growth results will be presented. \newline \newline References: \newline [1] H.A. Ejalonibu, M.P. Bradley, G. Sarty “The effect of step-wise surface nitrogen doping in MPECVD grown polycrystalline diamonds”, Materials Science and Engineering: B 258, 114559 (2020) \newline [2] H.A. Ejalonibu, G.E. Sarty, and M.P. Bradley, “Optimal parameter(s) for the synthesis of nitrogen-vacancy (NV) centres in polycrystalline diamonds at low pressure”, J. Mater. Sci.: Mater. Electron. 30, 10369-10382 (2019).   

Live

The use of non-sinusoidal voltage waveforms with a fluorinated silicon plasma precursor has been deployed in the past to produce an electrode-selective silicon deposition process [1]. In this work, we aim to demonstrate an area selective Plasma Enhanced Chemical Vapor Deposition (PECVD) using a standard 13.56 MHz radio frequency excitation source and an Ar/SiF4/H2 plasma chemistry. We found that for specific plasma parameters, a microcrystalline silicon film is selectively grown on a SiNx surface while the AlOx surface remains pristine. This plasma chemistry plays a crucial role in this selectivity as the surface processes strongly depend on the deposition/etching balance, as controlled by the H2 flow rate (The growth mechanism and techniques of this chemistry are detailed in reference [2]). The deposition selectivity on a patterned substrate containing both SiNx and AlOx areas, as well as the influence of the plasma parameters, have been studied and will be presented. The analysis is accomplished by in-situ spectroscopic ellipsometry and Scanning Electron Microscopy (SEM). [1] J. Wang and E.V. Johnson, Plasma Sources Sci. Technol. 26 (2017) 01LT01. [2] Dornstetter JC, Bruneau B, Bulkin P, Johnson EV, Roca i Cabarrocas P, J. Chem. Phys. 140, 234706 (2014   

Plasma Ion Doping for Semiconductor Applications

Plasma doping (PD) provides a potential solution in the search for a shallow, active or high concentration doping method that leaves minimum physical damages. That overcomes the limitations of conventional ion implantation in semiconductor applications. In this work, processes with Si and Sn ion doping into III-V material and processes with Si and N ion doping into HfO2 high-k material have been studied in a high density plasma system. AFM, SIMS, HR-TEM/EDX and XPS have been employed to characterize the effects of the main PD process parameters (plasma source power, gas pressure, bias power and processing time) on dopant depth profile, dopant concentration, doped material surface damage and modification. It is confirmed that ion density and energy determine dopant depth profile. With optimized process parameters, bias power is the most reliable and repeatable input parameter to use to define dopant depth profile and concentration. Additionally, bias power plays a primary role in modulating a process into either ion doping, film deposition or sputtering etching. Finally, an optimized plasma doping process has been developed that achieves sheet resistance reduction for InGaAs as channel materials in a CMOS logic device.