Mobility Enhancement in P-Type SnO Thin-Film Transistors via Ni Incorporation by Co-Sputtering

• Published in: IEEE electron device letters 2022-02, Vol.43 (2), p.228-231
• Main Authors: Hsu, Shu-Ming, Yang, Cheng-En, Lu, Min-Hsuan, Lin, Yi-Ting, Yen, Hung-Wei, Cheng, I-Chun
• Format: Article
• Language: English
• Subjects: CMOS; Co-sputtering; Electric power distribution; Flexible components; Glass substrates; high mobility; Magnetron sputtering; Nanoclusters; Nickel; Optical films; oxide semiconductor; p-type; P-type semiconductors; Phase transitions; Photonic band gap; Polycrystals; Semiconductor devices; Semiconductors; Spectroscopy; Substrates; Temperature measurement; Thin film transistors; thin-film transistor; tin; Tin oxides
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2021.3136966

Oxide semiconductors have been considered one of the most promising candidates for flexible electronics applications owing to their low process temperatures and good reliability. However, the low mobility of p-type oxide semiconductors limits the performance of flexible oxide-TFT-based CMOS technology. In this study, p-type SnO x :Ni thin films were deposited by reactive rf magnetron co-sputtering, a technique compatible with the current industrial semiconductor manufacturing technology, from Sn and Ni targets. As the Ni-gun power increased, the distribution of Ni in the SnO x :Ni thin film changed from a more uniform dispersion to nanoclusters, resulting in the crystalline phase transition of SnO x :Ni from \alpha -SnO (110)-dominant polycrystalline to amorphous and then to \alpha -SnO (101)-dominant polycrystalline. A high-mobility inverted-staggered p-type SnO x :Ni TFT was then fabricated on a glass substrate with a maximum process temperature of 225°C, which is compatible with flexible polymeric substrates. The TFT fabricated at an optimal Ni-gun power of 42 W exhibited an impressive field-effect mobility of 11 cm 2 V −1 s −1 and on current of 35.2 ~\mu \text{A} per channel width-to-length ratio; these values are comparable to those of a typical n-type oxide TFT. These results should contribute toward flexible oxide-TFT-based CMOS technology.