Reaction of cyanide ions with copper on Si surfaces and its use for Si cleaning |
| |
Authors: | Yueh-Ling Liu Hitoo Iwasa Shigeki Imai |
| |
Affiliation: | a Institute of Scientific and Industrial Research, Osaka University, CREST, Japan Science and Technology Organization, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan b System Solutions Planning Department, Electronic Components & Devices, Sharp Corporation, 2613-1, Ichinomoto-cho, Tenri, Nara 632-8567, Japan |
| |
Abstract: | A Si cleaning method has been developed by use of potassium cyanide (KCN) dissolved in methanol. When silicon dioxide (SiO2)/Si(1 0 0) specimens with 1014 atom/cm2 order copper (Cu) contaminants are immersed in 0.1 M KCN solutions of methanol at 25 °C, the Cu concentration is reduced to below the detection limit of total X-ray fluorescence spectrometer of ∼3 × 109 atoms/cm2. X-ray photoelectron spectra show that the thickness of the SiO2 layers is unchanged after cleaning with the KCN solutions. 1014 cm−2 order Cu contaminants on the Si surface can also be removed below ∼3 × 109 atoms/cm2, without causing contamination by potassium ions. UV spectra show that Cu-cyano complex ions are formed in the KCN solutions after the cleaning. The main Cu species in the KCN solutions is ions with the concentration of []:[Cu+] = 1:1.6 × 1023. Even when the KCN solutions are contaminated with 64 ppm Cu2+ ions in the solutions, which form ions, the cleaning ability does not decrease, showing that ions are not re-adsorbed. The KCN solutions can also passivate defect states such as Si/SiO2 interface states, leading to the improvement of characteristics of Si devices. |
| |
Keywords: | Cleaning Silicon Potassium cyanide Copper Defect passivation |
本文献已被 ScienceDirect 等数据库收录! |
|