Al 2 O 3 thin films were deposited on Si substrates by atomic layer deposition ͑ALD͒ using Al(CH 3 ) 3 ͑trimethylaluminum, TMA͒ as a metal source and (CH 3 ) 2 CHOH ͑isopropyl alcohol, IPA͒ as an oxygen source at 250°C. The film growth rate is saturated at 0.8 Å/cycle, and it is slightly lower than that for the procedure which uses water vapor instead of IPA. The as-deposited film has a stoichiometry close to Al 2 O 3 ͑Al/O ratio ϳ2:3.1͒ and the residual carbon content of the films is below the detection limit of secondary ion mass spectroscopy. An interface oxide between the Al 2 O 3 film and Si-substrate was not detectable on the asdeposited film by transmission electron microscopy. However, after annealing at 800°C for 5 min, an interface oxide is newly formed even under the neutral ambient of Ar, and it grows thicker under the oxidizing ambient of O 2 . That is, oxygen, which is needed for forming the interface oxide during the annealing process is supplied from both of the ambient oxygen and the excess oxygen in the films. Thus, although the loss of dielectric constant is inevitable during the annealing process, it can be minimized by using IPA in Al 2 O 3 ALD.As the size of microelectronic devices is scaled down, oxide films with high dielectric constants are required for gate and capacitor dielectrics. Even though SiO 2 is an excellent dielectric material in many features, the preparation of reliable SiO 2 films thinner than 30 Å is difficult, because of the quantum mechanical tunneling of electrons, which generates a large leakage current across the films. 1 Thus, an alternative oxide film with higher dielectric constant than SiO 2 is needed. 2 In this respect, Al 2 O 3 has been considered as a possible candidate for gate oxides as well as Ta 2 O 5 , HfO 2 , and ZrO 2 . 3-5 Also, Al 2 O 3 is considered as a promising capacitor dielectric, which can replace silicon oxynitride ͑SiON͒ in future dynamic random access memories ͑DRAM͒. 6 In addition, Al 2 O 3 has been recently regarded as a good passivation layer, which can prevent hydrogen penetration into the active region of semiconductor devices. 7 In preparing high-dielectric metal oxides with a thickness in the subhundred angstrom range, atomic layer deposition ͑ALD͒ attracts considerable interest owing to its inherent merits in thin film depositions, such as a digital controllability of film thickness on an atomic scale, a superior conformal deposition on three-dimensional structures, and no particle generation, etc. 8-10 In typical ALD of metal oxide thin films, H 2 O has been most widely used as the oxygen source. [11][12][13][14][15][16] However, by using H 2 O an unwanted interface oxide may be formed between the metal oxides and Si substrates, and it is thought that the interface oxide is composed mainly of SiO x , as the result of the reaction between H 2 O and the Si substrates during the initial stage of the ALD. Hence, the interfusion of the interface oxide would be expected to reduce the dielectric constant of the deposited thin films. 17-19 Th...

Background and objective: Education based on agricultural experience in school gardens is coming to the fore as a solution to reduce the negative effect of rapid urbanization and the development of information technology (IT) on students. Accordingly, this study aimed to investigate how parents of elementary, middle, and high school students in Korea perceive the value of education service using school gardens, as well as their willingness to participate in and pay for such service, and to utilize the results in a quantitative assessment of the socioeconomic value of the education service. Methods: A contactless online survey on the perceived value of education service using school gardens was conducted on 1,010 parents of elementary, middle, and high school students in Korea's five major districts from October 22 to 26 (5 days) of 2020 by M, a Korean specialized survey agency. The data collected was analyzed using SPSS for Windows 25.0 and Excel to obtain the frequency and ratio of each measured item. Results: The respondents had an average of 1.83, of which 52.8% were male. 55.3% of the respondents were aware of the education service using school gardens, and 27.9% experienced the service. When asked if they saw the educational service using school gardens as necessary, 79% answered in the affirmative. In terms of the difference in perception of the need for the service according to experience, 91.8% of the parents who experienced the service responded that it was necessary, indicating that it is important to provide opportunities to experience this service to expand the scope of service. 54.9% of all respondents responded they were willing to pay the costs required for school gardens. When income tax was used as a payment method, the average amount parents were willing to pay was 13,193 KRW, and the tax rate was 2.02%. Based on experience, those who experienced this service had a higher need and willingness to pay for the service than those who had not experience, but the actual amount or tax rate was low as they knew how it was operated. Conclusion: As basic research on the assessment of the value of agricultural experience education using school gardens, this study determined how parents perceive this form of education service as well as their willingness to participate and pay for the service. These findings can be used to systemize the assessment indicators and promote the value of the education service using school gardens, allowing students to maintain a healthy and happy school life through agricultural experience.

Background and objective The vitalization of urban agriculture has increased various forms of experience-based education using school gardens, which raised the importance of school gardens in terms of value as well as the need to develop an implementation system for education-based agricultural experience service using school gardens. Thus, we reset the evaluation indicators from the previous study to establish objective evaluation indicators that enable quantitative comparison of school garden education services. Methods Analytic hierarchy process (AHP) and direct question (DQ) surveys were conducted on 20 experts from October 12 to 19, 2020 after establishing the purpose and subjects of evaluation, and then the weights were calculated using the Expert Choice 2010 program. Results First, we analyzed the problems of the previous indicators by categorizing the performance indicators and comparing and verifying them with six requirements of valuation. Then, we added ‘welfare values’ and established sub-indicators accordingly. The importance of value indicator in AHP was in the order of education values (0.544), health values (0.182), welfare values (0.164), environmental values (0.062), and economic values (0.049). The importance of environmental and economic values was relatively low, less than 0.1. The importance of sub-indicators was highest in cultivating character (0.144), followed by enhancing ecological sensitivity (0.141) > promoting mental health (0.134) > cultivating agricultural literacy (0.120) > improving social skills (0.104). And mitigating climate change in environmental values was lowest (0.009). Increase in income was the lowest (0.036). This can be regarded as the expression of change to increase the educational effect based on collective life and the connotative meaning of ‘school’. In the case of DQ, the AHP weight and order were the same, but the environmental and economic values were relatively low, and the result was different from AHP weight. For sub-indicators, the importance in DQ was highest in promoting mental health (0.136), followed by promoting physical health (0.085), ]cultivating character (0.082), social integration (0.072), and enhancing ecological sensitivity (0.071). After reviewing related experts, we came up with 5 evaluation indicators and 16 sub-indicators for school garden education service, which are objective evaluation indicators that enable quantitative comparison. Conclusion In the future, we will validate the socioeconomic values of school garden education services and contribute to revitalizing school gardens by establishing policy alternatives for effective operation and management of school gardens.