Influence of Surface Roughness on the Dynamics and Crystallization of Vapor-Deposited Thin Films

Unni, Aparna Beena; Winkler, Roksana; Duarte, Daniel M.; Chat, Katarzyna; Adrjanowicz, Karolina

doi:10.1021/acs.jpcb.2c04541

Cited by 14 publications

(5 citation statements)

References 70 publications

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“…As Δα increased, the grain size increased and then decreased, while the twin grain boundary density exhibited the opposite trend. It is known that both strain and roughness in thin films affect the nucleation frequency and growth rate 14 , 51 – 53 . The fact that the Ge grain size varied for the SiO 2 , Si, and CaF 2 samples with similar roughness suggests that the strain applied to the a-Ge layer during temperature rise affects the crystal growth (Fig.…”

Section: Resultsmentioning

confidence: 99%

Strain-dependent grain boundary properties of n-type germanium layers

Igura,

Nozawa,

Ishiyama

et al. 2024

Sci Rep

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Polycrystalline Ge thin films have attracted considerable attention as potential materials for use in various electronic and optical devices. We recently developed a low-temperature solid-phase crystallization technology for a doped Ge layer and achieved the highest electron mobility in a polycrystalline Ge thin film. In this study, we investigated the effects of strain on the crystalline and electrical properties of n-type polycrystalline Ge layers. By inserting a GeOx interlayer directly under Ge and selecting substrates with different coefficients of thermal expansion, we modulated the strain in the polycrystalline Ge layer, ranging from approximately 0.6% (tensile) to − 0.8% (compressive). Compressive strain enlarged the grain size to 12 µm, but decreased the electron mobility. The temperature dependence of the electron mobility clarified that changes in the potential barrier height of the grain boundary caused this behavior. Furthermore, we revealed that the behavior of the grain boundary barrier height with respect to strain is opposite for the n- and p-types. This result strongly suggests that this phenomenon is due to the piezoelectric effect. These discoveries will provide guidelines for improving the performance of Ge devices and useful physical knowledge of various polycrystalline semiconductor thin films.

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Section: Resultsmentioning

confidence: 99%

Strain-dependent grain boundary properties of n-type germanium layers

Igura,

Nozawa,

Ishiyama

et al. 2024

Sci Rep

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“…Alkoxysilane and chlorosilane SAM is the most common class of SAMs used in the functionalization on a Si substrate due to the simple processing condition to obtain covalent bonding between the organic SAM and the inorganic Si substrate . However, the poor thermal stability of silane-based SAM and their tendency to self-polymerize could be detrimental in microelectronic processing. ,− To overcome the disadvantages of alkoxysilane-based SAM, various groups have investigated phosphonic acid-based SAM for the deposition of a single functional monolayer on Al 2 O 3 . While the functionalization and thermal stability of phosphonic acid-based SAM have been thoroughly investigated on the Al 2 O 3 substrate, the thermal stability of phosphonic acid-SAM on Si has never been explored.…”

Section: Resultsmentioning

confidence: 99%

Thermal Stability and Orthogonal Functionalization of Organophosphonate Self-Assembled Monolayers as Potential Liners for Cu Interconnect

Chou,

Chang,

Keng

2023

ACS Omega

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In this study, we investigated the thermal stabilities of butylphosphonic acid (BPA) and aminopropyltriethoxysilane (APTES) self-assembled monolayers (SAM) on a Si substrate. The thermal desorption and the thermal cleavage of the BPA and APTES SAM film on the Si substrate were studied by X-ray photoelectron spectroscopy (XPS) upon thermal treatment from 50 to 550 °C. XPS analyses show that the onset of the thermal desorption of the APTES monolayer occurs at 250 °C and the APTES SAM completely decomposed at 400 °C. Conversely, BPA SAM on Si shows that the onset of thermal desorption occurs at 350 °C, and the BPA SAM completely desorbed at approximately 500 °C. Our study revealed that the organophosphonate SAM is a more stable SAM in modifying the dielectric sidewalls of a Cu interconnect when compared to organosilane SAM. To overcome the spontaneous reaction of the organophosphonate film on the metal substrate, a simple orthogonal functionalization method using thiolate SAM as a sacrificial layer was also demonstrated in this study.

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“…Surface roughening produces abundant cracks in the supported layers, which could be beneficial when tuning the physical and chemical properties [ 22 , 36 ]. A rough substrate accelerates the iodination of the supported Cu layer due to the facile infiltration of iodine gas through the abundant grain boundaries.…”

Section: Discussionmentioning

confidence: 99%

Thermoelectric Sensor with CuI Supported on Rough Glass

Panama,

Lee

2024

Nanomaterials

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Thermoelectric generators convert heat into a potential difference with arrays of p- and n-type materials, a process that allows thermal energy harvesting and temperature detection. Thermoelectric sensors have attracted interest in relation to the creation of temperature and combustible gas sensors due to their simple operation principle and self-powering ability. CuI is an efficient p-type thermoelectric material that can be readily produced from a Cu layer by an iodination method. However, the vapor iodination of Cu has the disadvantage of weak adhesion on a bare glass substrate due to stress caused by crystal growth, limiting microfabrication applications of this process. This work presents a rough soda-lime glass substrate with nanoscale cavities to support the growth of a CuI layer, showing good adhesion and enhanced thermoelectric sensitivity. A rough glass sample with nanocavities is developed by reactive ion etching of a photoresist-coated glass sample in which aggregates of carbon residuals and the accumulation of NaF catalyze variable etching rates to produce local isotropic etching and roughening. A thermoelectric sensor consists of 41 CuI/In-CoSb3 thermoelectric leg pairs with gold electrodes for electrical interconnection. A thermoelectric leg has a width of 25 μm, a length of 3 mm, and a thickness of 1 μm. The thermoelectric response results in an open-circuit voltage of 13.7 mV/K on rough glass and 0.9 mV/K on bare glass under ambient conditions. Rough glass provides good mechanical interlocking and introduces important variations of the crystallinity and composition in the supported thermoelectric layers, leading to enhanced thermopower.

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Influence of Surface Roughness on the Dynamics and Crystallization of Vapor-Deposited Thin Films

Cited by 14 publications

References 70 publications

Strain-dependent grain boundary properties of n-type germanium layers

Strain-dependent grain boundary properties of n-type germanium layers

Thermal Stability and Orthogonal Functionalization of Organophosphonate Self-Assembled Monolayers as Potential Liners for Cu Interconnect

Thermoelectric Sensor with CuI Supported on Rough Glass

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