0603040 - FZÚ 2025 RIV DE eng A - Abstrakt
Szabó, Ondrej - Vanko, Gabriel - Jackivová, Rajisa - Gedeonová, Zuzana - Aubrechtová Dragounová, Kateřina - Hruška, Karel - Kromka, Alexander
Thermochemical etching of polycrystalline diamond films by nickel.
International Conference on Diamond and Carbon Materials (ICDCM2024). Dresden: Elsevier, 2024.
[International Conference on Diamond and Carbon Materials /34./. 01.09.2024-05.09.2024, Dresden]
Grant CEP: GA MŠMT(CZ) LUASK22147
Institucionální podpora: RVO:68378271
Klíčová slova: polycrystalline diamond * thermochemical reaction * micron-sized patterns fabrication * high-temperature water vapor
Obor OECD: Materials engineering

The physical and electronic properties of diamond make it essential for various applications such as electronics, photonics and quantum technologies. However, producing micron-sized patterns down to tens of micrometers in depth is still challenging due to the diamond's exceptional hardness and chemical inertness. Dry etching processes are limited by re-sputtering of the mask material and expensive vacuum equipment. Thermally-induced chemical graphitization of diamond by nickel has opened up new challenges in transforming diamond to the sp2-carbon form [10.1021/acs.jpcc.7b12334, 10.1021/acsnano.9b00692]. Moreover, once the method is utilized under high-temperature water vapor conditions, hundreds of micrometers deep etchings are produced in monocrystalline diamond [10.1038/s41598-018-25193-2]. This study focuses on deep etching of polycrystalline diamond films using Ni as the catalyst in a thermochemical process conducted at different gas compositions and temperatures (900-975°C). We investigate the impact of process parameters on the etching process in terms of the etching rate and selectivity. Only a minimal etching was observed under the Ni mask in hydrogen microwave plasma conditions. Introducing CO2 into the gas mixture enhanced the etching rate by a factor of 2-3, but unfortunately, the etching was also observed over the unmasked diamond regions. Only the use of water vapor demonstrated the etching selectivity. However, this etching reveals dependence on the total process pressure. In the low-pressure range (5÷50 Torr), catalytic etching revealed a maximum depth of 2-3 µm before slowing down due to the formation of a graphitized cap around Ni. Increasing the pressure to atmospheric levels resolved this limitation, and the structures with depths up to tens of micrometers were formed at an etching rate of 1 um/min.
Trvalý link: https://hdl.handle.net/11104/0364519