Chen Kuan-Chieh, Wu Jiancheng, Pooja Pheiroijam, Chin Albert
Department of Electronics Engineering, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan.
Nanomaterials (Basel). 2025 Apr 23;15(9):640. doi: 10.3390/nano15090640.
Using novel SiO surface passivation and ultraviolet (UV) light anneal, a 12 nm thick SnO p-type FET (pFET) shows hole effective mobilities (µ) of more than 100 cm/V·s and 31.1 cm/V·s at hole densities (Q) of 1 × 10 and 5 × 10 cm, respectively. To further improve the on-current/off-current (I/I), an ultra-thin 7 nm thick SnO nanosheet pFET shows a record-breaking I/I of 6.9 × 10 and remarkable µ values of ~70 cm/V·s and 20.7 cm/V·s at Q of 1 × 10 cm and 5 × 10 cm, respectively. This is the first report of an oxide semiconductor transistor achieving a hole effective mobility µ that reaches 20% of that in single-crystal Si pFETs at an ultra-thin body thickness of 7 nm. In sharp contrast, the control SnO nanosheet pFET without surface passivation or UV anneal exhibits a small I/I of 1.8 × 10 and a µ of only 6.1 cm/V·s at 5 × 10 cm Q. The enhanced SnO pFET performance is attributed to reduced defects and improved quality in the SnO channel, as confirmed by decreased charges related to sub-threshold swing (SS) and threshold voltage (Vth) shift. Such a large improvement is further supported by the increased Sn after passivation and UV anneal, as evidenced by X-ray photoelectron spectroscopy (XPS) analysis. The I/I ratio exceeding six orders of magnitude, remarkably high hole µ, and excellent two-month stability demonstrate that this pFET is a strong candidate for integration with SnON nFETs in next-generation ultra-high-definition displays and monolithic three-dimensional integrated circuits (3D ICs).
通过采用新型的SiO表面钝化和紫外（UV）光退火工艺，一个12纳米厚的SnO p型场效应晶体管（pFET）在空穴密度（Q）分别为1×10和5×10厘米时，展现出超过100厘米²/伏·秒和31.1厘米²/伏·秒的空穴有效迁移率（µ）。为了进一步提高开电流/关电流（Ion/Ioff），一个超薄的7纳米厚的SnO纳米片pFET在Q为1×10厘米和5×10厘米时，分别展现出破纪录的6.9×10的Ion/Ioff以及约70厘米²/伏·秒和20.7厘米²/伏·秒的显著µ值。这是关于氧化物半导体晶体管的首次报道，该晶体管在7纳米的超薄体厚度下实现了空穴有效迁移率µ达到单晶硅pFET中迁移率的20%。形成鲜明对比的是，未进行表面钝化或UV退火的对照SnO纳米片pFET在5×10厘米的Q时，展现出1.8×10的小Ion/Ioff和仅6.1厘米²/伏·秒的µ。SnO pFET性能的增强归因于SnO沟道中缺陷的减少和质量的改善，这通过与亚阈值摆幅（SS）和阈值电压（Vth）偏移相关的电荷减少得到证实。钝化和UV退火后Sn含量的增加进一步支持了如此大的性能提升，这由X射线光电子能谱（XPS）分析所证明。超过六个数量级的Ion/Ioff比、非常高的空穴µ以及出色的两个月稳定性表明，这种pFET是下一代超高分辨率显示器和单片三维集成电路（3D IC）中与SnON nFET集成的有力候选者。
