Fluorinated Oxynitride Films Prepared by Temperature-Difference Deposition Method Using the Aqueous Solution of Hydrofluorosilicic Acid and Ammonium Hydroxide

• Main Authors: Wu-Hung Shieh, 謝武鴻
• Other Authors: Ming-Kwei Lee
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/17623097606060992270

碩士 === 國立中山大學 === 電機工程學系研究所 === 90 === The advantages of LPD method, low temperature process, low cost, conformal growth (good step coverage), selective growth and inexpensive deposition system make the method of LPD versatile in IC fabrication. LPD-SiOF is a potential method to replace traditional method of SiOF deposition. But, some drawbacks, including slightly low dielectric constant and poor performance of J-E relationship, still exist in LPD-SiOF process. In order to improve these shortcomings, with incorporating NH4OH into the LPD solution in this experiment, the SiOF:N film with high quality and low dielectric constant can be grown on Si by the TD-LPD method. In this study, the growth rate can be controlled well within 90~550 Å/h corresponding to the NH4OH concentration range of 0.1~0.8 M at the temperature range of 23~40 °C. As TD-LPD-SiOF:N film deposited with 0.8 M NH4OH incorporation, the refractive index for can be kept at a constant 1.431 and the P-etch rate can be kept between 18.3 and 19.2 Å/s during the deposition temperature changes. The best experimental condition is found that incorporating 0.8 M NH4OH will get good results. If the concentration of 0.8 M is higher or lower than 0.8 M, the electrical characteristic will become poor. A model for TD-LPD-SiOF:N deposition mechanism is proposed. From the analysis of SIMS depth profile, the deposited film can be suggested that it is a combination of N-less LPD-SiOF film and N-rich accumulated interfacial layer. The properties of N-rich accumulated layer at the interface show the least effective oxide charges and lowest leakage current density. As the thickness of TD-LPD-SiOF:N film is 800 Å, the film has the best electrical characteristic. When the thickness is below or above 800 Å, all the properties become poor. TD-LPD-SiOF:N film deposited at 40 °C with 0.8 M NH4OH incorporation with a thickness of 800 Å has the best physical, chemical, electrical properties. The F content for deposited film can reach 9.8 atom %. The dielectric constant can drop to about 3.07.