Impacts of Ammonia Gas Plasma Surface Treatment on Polycrystalline-Silicon Junctionless Thin-Film Transistor

Autor: Shen-Ming Luo, Cai-Jia Tsai, Ming-Jhe Li, Ting-Hsuan Chang, Jiun-Hung Lin, Yan-Shiuan Chang, William Cheng-Yu Ma, Po-Jen Chen, Jhe-Wei Jhu
Rok vydání: 2021
Předmět:
Zdroj: IEEE Transactions on Plasma Science. 49:26-32
ISSN: 1939-9375
0093-3813
Popis: The impacts of ammonia gas (NH3) plasma treatment on the performance and positive gate bias stress (PGBS) of polycrystalline-silicon (poly-Si) junctionless thin-film transistor (JL-TFT) are studied. A −0.785-V threshold voltage ( $V_{\mathrm {TH}}$ ) shift of JL-TFT due to the NH3 plasma treatment is observed, which is attributed to the fixed oxide charge effect of the plasma-induced interfacial layer (PIL). In addition, the transconductance of JL-TFT with the NH3 plasma treatment is enhanced by ~2.73 times due to the trap state passivation of grain boundaries in the poly-Si, and the ON-state current ( $I_{\mathrm {ON}}$ ) is enhanced by ~2.91 times. In addition to the performance enhancement of JL-TFT by the plasma process, the $V_{\mathrm {TH}}$ shift of poly-Si JL-TFT under PGBS is suppressed from −0.240 to −0.063 V after the plasma treatment. It is attributed to the less degradation of insulator/channel interface due to the growth of PIL by the plasma process. Moreover, the $I_{\mathrm {ON}}$ degradation of JL-TFT after PGBS is also improved from −19% to −16% after the plasma treatment. As the carrier transport of JL-TFT is the bulk conduction rather than the surface conduction of conventional inversion-mode TFT, the degradation of insulator/channel interface would exhibit less impacts on the $I_{\mathrm {ON}}$ . The improvement of performance and PGBS of JL-TFT by the NH3 plasma treatment would be beneficial to the application of 3-D integrated circuits.
Databáze: OpenAIRE