Donghyuk Shin - Academia.edu (original) (raw)
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Papers by Donghyuk Shin
Thin Solid Films, 2020
The gate-all-around structure is a promising candidate for future generations of advanced metal-o... more The gate-all-around structure is a promising candidate for future generations of advanced metal-oxide semiconductor field-effect transistor technologies, as it provides higher drive current and low-power operation. The commonly-suggested nanowire structure uses a selective etching technique in the silicon/silicon-germanium multilayer to reveal the channel area. The revealed Si surface is rough, however, due to the missing atoms and remnants of Si 1-x Ge x. This leads to increased interfacial state density, which degrades device performance, such as subthreshold voltage swing. Regarding the usage of high-k metal gates on the channel area, the issue of this rough surface, and the subsequent increase of the dangling bonds after etching, should be properly addressed. In this study, we report the enhanced roughness and density of interface state by applying a Si capping layer. The epitaxial Si 0.87 Ge 0.13 layer, with a thickness of 30 nm on the Si substrate, was removed by an etchant consisting of nitric acid, hydrofluoric acid, and acetic acid, after which a 1-nm thick Si capping layer was epitaxially grown onto the surface. Atomic Force Microscopy was used to measure the roughness, and X-ray Photoelectron Spectroscopy was conducted to characterize the atomic bonds on the surface. A 10-nm thick SiO 2 film was deposited using the Atomic Layer Deposition process to characterize the capacitance-voltage curve and interface trap density. The Si-capped sample exhibited half of the surface roughness of the un-capped sample, and exhibited a 30% lower interface trap density, by mitigating the impact of wet etching.
AIP Advances, 2019
Titanium dioxide (TiO 2) films were deposited by plasma enhanced atomic layer deposition (PE-ALD)... more Titanium dioxide (TiO 2) films were deposited by plasma enhanced atomic layer deposition (PE-ALD) system using tetrakis-dimethylamidotitanium (TDMAT) at 250 ○ C. We applied a new source feeding method, known as Discrete Feeding Method (DFM), to PE-ALD TiO 2 process for comparing the deposition rate, the physical and electrical film properties with the films deposited by conventional ALD method. Various analytical studies were carried out to investigate the change of TiO 2 thin film characteristics due to DFM application. As a result, the optimal process condition was obtained with high physical properties and productivity while keeping electrical characteristics equivalent to those of the conventional ALD condition.
Thin Solid Films, 2020
The gate-all-around structure is a promising candidate for future generations of advanced metal-o... more The gate-all-around structure is a promising candidate for future generations of advanced metal-oxide semiconductor field-effect transistor technologies, as it provides higher drive current and low-power operation. The commonly-suggested nanowire structure uses a selective etching technique in the silicon/silicon-germanium multilayer to reveal the channel area. The revealed Si surface is rough, however, due to the missing atoms and remnants of Si 1-x Ge x. This leads to increased interfacial state density, which degrades device performance, such as subthreshold voltage swing. Regarding the usage of high-k metal gates on the channel area, the issue of this rough surface, and the subsequent increase of the dangling bonds after etching, should be properly addressed. In this study, we report the enhanced roughness and density of interface state by applying a Si capping layer. The epitaxial Si 0.87 Ge 0.13 layer, with a thickness of 30 nm on the Si substrate, was removed by an etchant consisting of nitric acid, hydrofluoric acid, and acetic acid, after which a 1-nm thick Si capping layer was epitaxially grown onto the surface. Atomic Force Microscopy was used to measure the roughness, and X-ray Photoelectron Spectroscopy was conducted to characterize the atomic bonds on the surface. A 10-nm thick SiO 2 film was deposited using the Atomic Layer Deposition process to characterize the capacitance-voltage curve and interface trap density. The Si-capped sample exhibited half of the surface roughness of the un-capped sample, and exhibited a 30% lower interface trap density, by mitigating the impact of wet etching.
AIP Advances, 2019
Titanium dioxide (TiO 2) films were deposited by plasma enhanced atomic layer deposition (PE-ALD)... more Titanium dioxide (TiO 2) films were deposited by plasma enhanced atomic layer deposition (PE-ALD) system using tetrakis-dimethylamidotitanium (TDMAT) at 250 ○ C. We applied a new source feeding method, known as Discrete Feeding Method (DFM), to PE-ALD TiO 2 process for comparing the deposition rate, the physical and electrical film properties with the films deposited by conventional ALD method. Various analytical studies were carried out to investigate the change of TiO 2 thin film characteristics due to DFM application. As a result, the optimal process condition was obtained with high physical properties and productivity while keeping electrical characteristics equivalent to those of the conventional ALD condition.