| 학회 | 한국재료학회 |
| 학술대회 | 2014년 봄 (05/15 ~ 05/16, 창원컨벤션센터) |
| 권호 | 20권 1호 |
| 발표분야 | A. 전자/반도체 재료(Electronic and Semiconductor Materials) |
| 제목 | Etching Properties of Magnetic Tunnel Junction Materials using CO/NH3 Gas Mixtures in Pulsed-bias ICP System |
| 초록 | Next generation memory devices have been strongly studied to overcome the limited memory performance. Among these non-volatile memory devices, spin transfer torque magnetic random access memory (STT-MRAM) is one of the promising candidates due to high density storage, fast access time, infinite rewrite, and low operating voltage. In the STT-MRAM, magnetic tunnel junction (MTJ) multilayer is the most important part because the main data are recorded in the MTJ stack. Therefore, the precise etching of MTJ multilayer for the high reliable and operating performance STT-MRAM is required. The etching of MTJ stack has some problems because it is difficult to form volatile compounds in the conventional etching system with conventional etch gas mixtures. Also, when conventional halogen gas mixtures were used, the corrosion of the MTJ materials is another problem. So, several research groups have investigated to increase the formation of volatile compounds between etchant gas and MTJ materials using non-corrosive gases such as CO/NH3, CH3OH, etc. However, these etching gases do not easily form volatile compounds. As a result, the etch residue remain the etched MTJ surface and it causes other problems. In this study, to increase the chemical reaction between MTJ materials and etch gases for high etch selectivity during etching process, an rf pulsed-biasing technique is applied to substrate in an ICP system and the etch characteristics of MTJ related materials such as CoFeB, FePt, Ru and W were investigated. The MTJ related materials such as CoFeB, MgO, FePt, and W were used to compare the etch characteristics. These materials were prepared using a co-sputter deposition technique and were etched using a CO/NH3 gas combination. For an effective chemical reaction, and the CO/NH3 gas flow rate ratio was fixed at 12.5 sccm/37.5 sccm. The ICP source power of 500 W and the time-averaged DC bias voltage of –300 V were used to etch the materials. The process pressure and the total flow rate were fixed at 5 mTorr and 50 sccm, respectively. |
| 저자 | 윤덕현, 염근영 |
| 소속 | 성균관대 |
| 키워드 | pin transfer torque magnetic random access memory (STT-MRAM); magnetic tunnel junction (MTJ); Inductively coupled plasma(ICP) |
