| 학회 | 한국재료학회 |
| 학술대회 | 2014년 봄 (05/15 ~ 05/16, 창원컨벤션센터) |
| 권호 | 20권 1호 |
| 발표분야 | A. 전자/반도체 재료(Electronic and Semiconductor Materials) |
| 제목 | Investigation about TaN diffusion barrier properties of Cu gate TFT with Al2O3 and HfO2 gate insulator |
| 초록 | As displays become larger and need higher resolution, lowering the propagation delay become important issue for display uniformity. One of solutions to transport electric signal faster, Copper (Cu) is rising as alternative candidate for gate metal interconnection because of its low resistivity below 2 μΩ•cm and higher resistance to electromigration compared to present gate metals such as Aluminum (Al) or Cu/Al alloy. However, Cu doesn’t have employed in current electrical devices due to its poor adhesion to glass substrates, ease of oxidation, and high tendency to diffuse into contact materials. Especially, diffusion of Cu into gate insulator layer in transistor devices leads to fast breakdown, so that many researchers investigate to solve it. To apply Cu as a practical gate electrode, it is necessary to investigate gate insulators and diffusion barriers with high resistance to Cu diffusion under high temperature and gate bias applied environments. Recently, several researches about insulator breakdown by Cu diffusion were reported such as in Al2O3 and HfO2.To fabricate thin film transistors (TFT) with Cu as a gate electrode, forming diffusion barrier is widely studied with various materials. To reduce Cu diffusions into the gate insulator, many Cu diffusion barriers such as Ta, TaN, TaC, AlOx, and Ru were studied.Among them, TaN is the most frequently used material Cu diffusion barrier in semiconductor due to its amorphous or stuffed nano-crystalline structure. Furthermore, TaN has a high melting point (3087 ˚C), and has high thermal stability because Ta does not forms compound with Cu. However, the study about Cu diffusion barrier properties of TaN used in TFTs using Cu as a gate electrode is rarely reported. In this report, we fabricated TFTs using Cu as a gate electrode with Al2O3 and HfO2 as gate insulators deposited by Atomic Layer Deposition (ALD) and investigated electrical characteristics of TFTs. And we compared the Cu diffusion protection properties between Al2O3 and HfO2 as gate insulators. Also, we performed bias thermal stability (BTS) tests on room temperature and 60 ˚C, and measured gate leakage characteristics of each device for evaluating stability of Cu-gate TFTs. |
| 저자 | 김동현, 김형준, 우황제, 남태욱, 정한얼 |
| 소속 | 연세대 |
| 키워드 | Cu diffusion barrier; TaN; TFT; BTS |
