NANO-POROUS SiOx THIN FILMS FOR APPLICATION OF LOW DIELECTRIC MATERIALS

Research Project

Project/Area Number	11650317
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Electronic materials/Electric materials
Research Institution	The University of Electro-Communications
Principal Investigator	UCHIDA Kazuo The University of Electro-Communications, Dept. of Electro-Communications, ASSOCIATE PROFESSOR, 電気通信学部, 助教授 (80293116)
Co-Investigator(Kenkyū-buntansha)	ONO Hiroshi The Unviersity of Electro-Communications, Dept. of Electro-Communications, RESEARCH ASSISTANT, 電気通信学部, 助手 (00134867)
Project Period (FY)	1999 – 2000
Project Status	Completed (Fiscal Year 2000)
Budget Amount *help	¥3,700,000 (Direct Cost: ¥3,700,000) Fiscal Year 2000: ¥1,900,000 (Direct Cost: ¥1,900,000) Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
Keywords	Gas evaporation Technique / Nano-porous SiOx / Low dielectric materials / X-ray total reflection method / Porosity / FT-IR / HMDS / カズ中蒸発法 / 空孔率 / 低誘電率材料 / 層間絶縁膜 / 酸化シリコンナノポーラス薄膜 / クラスター
Research Abstract	We have fabricated and characterized the nano-porous thin films of SiOx grown by Gasevaporation technique in oxygen atmosphere for the application of inter-dielectric in future VLSI technology. It was found that most of the samples had the dielectric constant below 2 as measured by the capacitance method and their porosity were over 90% as measured by the X-ray total reflection method. However, due to high porosity, water absorption into films, measured by FT-IR, was found to be inevitable and resulted in the increase of dielectric constant. In order to avoid this water absorption, we have proposed the HMDS (Hexamethyl disilan) method. We found that the dielectric constant of the film grown at 0.5 torr oxygen atmosphere with HMDS treatment was as low as 1.4. In comparison, we measured the dielectric constant of as-deposited sample in vacuum that was annealed at 623 K and found that it was as low as 1.3. On the other hand, we have fabricated nano-porous thin films of SiOx by post oxidation Si nano-porous grown by Gas-evaporation technique. These samples contained less absorbed water than SiOx samples grown by Gas-evaporation technique in oxygen atmosphere. Typical dielectric constant of these samples were as low as 1.4 without HMDS or high temperature annealing. These results prove that our SiOx films grown by simple Gas-evaporation technique are versatile and can be applied to future VLSI technology without modifying existing systems.