Silicon-based thin films as bottom electrodes in chalcogenide nonvolatile memories

✍ Scribed by Seung-Yun Lee; Sung-Min Yoon; Kyu-Jeong Choi; Nam-Yeal Lee; Young-Sam Park; Sang-Ouk Ryu; Byoung-Gon Yu; Sang-Hoon Kim; Sang-Heung Lee

• Book ID: 104002128
• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 461 KB
• Volume: 254
• Category: Article
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2007.07.097

✦ Synopsis

The effect of the electrical resistivity of a silicon-germanium (SiGe) thin film on the phase transition in a GeSbTe (GST) chalcogenide alloy and the manufacturing aspect of the fabrication process of a chalcogenide memory device employing the SiGe film as bottom electrodes were investigated. While p-type SiGe bottom electrodes were formed using in situ doping techniques, n-type ones could be made in a different manner where phosphorus atoms diffused from highly doped silicon underlayers to undoped SiGe films. The p-n heterojunction did not form between the p-type GSTand n-type SiGe layers, and the semiconduction type of the SiGe alloys did not influence the memory device switching. It was confirmed that an optimum resistivity value existed for memory operation in spite of proportionality of Joule heating to electrical resistivity. The very high resistivity of the SiGe film had no effect on the reduction of reset current, which might result from the resistance decrease of the SiGe alloy at high temperatures.