Deposition Temperature Dependence of Optical Properties of a-Si:H for Short-wave Near-infrared Filter by DC Sputtering

Kawamata, Yoshio; Itô, Hiroshi; Nikkuni, Hiroyuki; Ito, Mikio

doi:10.1380/vss.64.375

Cited by 2 publications

(7 citation statements)

References 23 publications

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“…The purpose of heating is to reduce defects by promoting structural relaxation and voids in the film caused by the Si−H 2 bond. However, it has been found in our previous studies [8] that when temperatures higher than 300°C are used for heating, the optical absorption increases owing to the increase in dangling bonds attributed to the thermal desorption of hydrogen. Therefore, the heating temperature was set at 200°C.…”

Section: Experimental Methodsmentioning

confidence: 67%

“…Table 1 lists the film deposition conditions. Based on our previous research [7,8], the basic conditions were a hydrogen partial pressure ratio of 30% and a sputter power of DC 400 W. Furthermore, the substrate was heated during the film deposition. The purpose of heating is to reduce defects by promoting structural relaxation and voids in the film caused by the Si−H 2 bond.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…For BPF, a-Si:H and SiO 2 were deposited under the conditions listed in Table 1. These were laminated into a Fabry-Perot type eight-layer single cavity structure using a silicon target, as in our previous studies [7,8]. The characteristics of the BPF were determined using transmittance measurements.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…These changes in optical constants are attributed to the thermal desorption of hydrogen, and it is considered that if the amount of desorption is smaller, the amount of change is smaller [7]. Thermal desorption of hydrogen due to post-annealing is considered to be affected by structural relaxation during film formation, hydrogen bond state, and film morphology [7,8,23]. The correlation between these trends and thermal durability in each process will be examined in Section IV.…”

Section: E Changes In Optical Characteristics After Post-annealingmentioning

confidence: 99%

“…To popularize a-Si:H as an optical film for SWNIR, we considered it important to clarify the influence of absorption in the short-wave region and durability, including the characteristics of the application, using a simple and stable film deposition process. Therefore, we prepared a-Si:H using a hydrogen-reactive direct current (DC) sput-tering method and examined its application in optical filters [7,8]. Thus far, we have obtained a relationship among hydrogen composition, substrate temperature, optical characteristics, and thermal durability.…”

Section: Introductionmentioning

confidence: 99%

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Substrate Potential Dependence of Optical Characteristics of a-Si:H for Shortwave Near-infrared Filter by DC and RF Sputtering

Kawamata

Itô

Nikkuni

et al. 2022

e-J. Surf. Sci. Nanotechnol.

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In this study, the substrate potential dependence of the film structures and optical characteristics of hydrogenated amorphous silicon (a-Si:H) prepared by reactive sputtering was investigated for application in short-wave near-infrared band pass filters (BPFs). During direct current (DC) sputtering, the substrate was charged to a negative potential, which was further increased by applying an RF bias. When the negative potential was large owing to the bias, the surface of the film became smooth owing to the ion bombardment. However, the refractive indices of the films decreased as the Si−H2 bonds increased. When radio frequency (RF) sputtering was used, the acceleration voltage of the ions decreased to 1/3; thus, structural relaxation was promoted. Consequently, a-Si:H with a high refractive index, low optical absorption, and high thermal durability, which are suitable for a narrow BPF, was obtained. The deterioration after annealing of the characteristics of the BPF using a-Si:H prepared by RF sputtering was reduced by half compared with DC sputtering.

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Section: Experimental Methodsmentioning

confidence: 67%

Section: Experimental Methodsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

Section: E Changes In Optical Characteristics After Post-annealingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Substrate Potential Dependence of Optical Characteristics of a-Si:H for Shortwave Near-infrared Filter by DC and RF Sputtering

Kawamata

Itô

Nikkuni

et al. 2022

e-J. Surf. Sci. Nanotechnol.

Self Cite

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Film structure and optical characteristics of a-Si:H prepared with a rotary table type layer-by-layer sputtering method for application in short-wave near-infrared filters

Kawamata¹,

Ono²,

Itô³

et al. 2022

Opt. Mater. Express

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The structure and optical properties of a hydrogenated amorphous silicon (a-Si:H) film for a short-wave near-infrared bandpass filter (BPF), fabricated using the rotary table type layer-by-layer (LbL) sputtering method, were evaluated. Although the extinction coefficient k tended to increase as the film thickness per cycle increased, the bonded hydrogen composition increased owing to an increase in the hydrogen partial pressure of the reactive plasma area, thereby decreasing k to 1 × 10−3 or less. Meanwhile, the occurrence of (Si–H2)n bonds was suppressed. Consequently, in contrast to reactive sputtering, it was found that the a-Si:H achieved via LbL sputtering has a high refractive index, low absorption characteristics, and high thermal durability suitable for BPFs, due to the chemical annealing effect.

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Deposition Temperature Dependence of Optical Properties of a-Si:H for Short-wave Near-infrared Filter by DC Sputtering

Cited by 2 publications

References 23 publications

Substrate Potential Dependence of Optical Characteristics of a-Si:H for Shortwave Near-infrared Filter by DC and RF Sputtering

Substrate Potential Dependence of Optical Characteristics of a-Si:H for Shortwave Near-infrared Filter by DC and RF Sputtering

Film structure and optical characteristics of a-Si:H prepared with a rotary table type layer-by-layer sputtering method for application in short-wave near-infrared filters

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