| 학회 | 한국재료학회 |
| 학술대회 | 2008년 가을 (11/07 ~ 11/07, 차세대융합기술연구원) |
| 권호 | 14권 2호 |
| 발표분야 | 전자재료 |
| 제목 | Deposition and Characterization of Bi doped Ge2Sb2Te5 Thin Films for Phase Change Random Access Memory Application |
| 초록 | As design rule is approaching to 50 nm node, the resistance based memories have been considered as promising candidates to replace the conventional charge based flash memory. Among the resistance based memories, PRAM(Phase change Random Access Memory) stores the digital data as different resistances of the phase change material between amorphous and crystalline phase. Although PRAM has superior performances, there are still some critical issues to be resolved i.e. reducing amorphization current for smaller driving transistor, which enables further scaling of the device. Ge2Sb2Te5 is the most well known phase change material for PRAM. Attempts has been made to improve the phase change properties of Ge2Sb2Te5 by doping various elements and compounds such as nitrogen, oxygen and SiO2. In this report Ge2Sb2Te5 was manipulated by doping Bi. By cosputtering Bi, Bi2Te3 and Ge2Sb2Te5, Bi was incorporated into Ge2Sb2Te5. When the amorphous Bi doped Ge2Sb2Te5 films were transformed into NaCl type cubic phase by thermal annealing at about 150oC, the resistivity of the film was reduced over 3 orders of magnitude, which was sufficient for device application. The Bi doped Ge2Sb2Te5 films showed lower amorphization voltage without having to increase the crystalline resistance and demonstrated faster crystallization speed than those of undoped Ge2Sb2Te5. Isothermal crystallization was observed using in-situ sheet resistance measurement. Effective crystallization energy of Bi-doped Ge2Sb2Te5 thin films was larger than that of undoped Ge2Sb2Te5, contradicting the observed faster crystallization of Bi-doped films. |
| 저자 | Jong Ho Lee1, Seung Wook Ryu1, Yeong Bae Ahn1, Se-Ho Lee2, Cheol Seong Hwang1, Hyeong Joon Kim1 |
| 소속 | 1Seoul National Univ., 2Hynix Semiconductor |
| 키워드 | Ge2Sb2Te5; Bismuth; phase change memory; chalgogenide |
