Huang Ching-Shuan, Shih Che-Chi, Tsai Wu-Wei, Woon Wei-Yen, Lien Der-Hsien, Chien Chao-Hsin
Institute of Electronics, National Yang Ming Chiao Tung University, Hsinchu 300093, Taiwan.
Pathfinding, Taiwan Semiconductor Manufacturing Company, Hsinchu 300091, Taiwan.
ACS Appl Mater Interfaces. 2025 Jan 22;17(3):5078-5085. doi: 10.1021/acsami.4c18435. Epub 2025 Jan 9.
Ultrathin indium oxide films show great potential as channel materials of complementary metal oxide semiconductor back-end-of-line transistors due to their high carrier mobility, smooth surface, and low leakage current. However, it has severe thermal stability problems (unstable and negative threshold voltage shifts at high temperatures). In this paper, we clarified how the improved crystallinity of indium oxide by using ultrahigh-temperature rapid thermal O annealing could reduce donor-like defects and suppress thermal-induced defects, drastically enhancing thermal stability. Not only does more crystalline indium oxide depict the high stability of threshold voltage in stringent high-temperature test environments and under positive bias, but it also shows much less degradation under forming gas annealing than as-deposited transistors. Furthermore, we also successfully solved the channel length-dependent threshold voltage problem, which is often observed in oxide transistors, by suppressing defects induced by the metal deposition process and metal doping.
超薄氧化铟薄膜因其高载流子迁移率、光滑表面和低漏电流，作为互补金属氧化物半导体后端晶体管的沟道材料展现出巨大潜力。然而，它存在严重的热稳定性问题（在高温下阈值电压不稳定且向负方向偏移）。在本文中，我们阐明了通过超高温快速热氧化退火提高氧化铟的结晶度如何减少类施主缺陷并抑制热致缺陷，从而大幅增强热稳定性。不仅结晶度更高的氧化铟在严苛的高温测试环境和正偏压下展现出阈值电压的高稳定性，而且在形成气体退火下其退化程度比沉积态晶体管小得多。此外，我们还通过抑制金属沉积过程和金属掺杂诱导的缺陷，成功解决了氧化物晶体管中常见的沟道长度依赖性阈值电压问题。
