Self-Aligned Spacer Doping in MoS2 High-κ Top-Gate Transistors
Journal
Advanced Functional Materials
ISSN
1616301X
Date Issued
2026
Author(s)
Huang, Kai-Chun
Lee, Che-Lun
Lin, Hung-Jui
Chen, Yu-Ting
Liu, Tsung-Hsin
Lu, Chang-Hua
Wang, Pin-Lin
Cheng, Chi-Chun
Hsieh, Cheng-Chieh
Shiue, Jessie
Yeh, Chao-Hui
Chiu, Po-Wen
Chen, Chia-Chun
Ho, Po-Hsun
Abstract
Because 2D materials are atomically thin and free of dangling bonds, integrating high-κ dielectrics and achieving spacer doping remain challenging using traditional atomic layer deposition (ALD) techniques and ion implantation method. Here, a “high-κ top-gate lift-off” strategy enabling the precise fabrication of underlap MoS2 field-effect transistors (FETs) with well-defined spacer regions is presented. A high-κ Erbium oxide (ErOx) dielectric, deposited by reactive thermal evaporation, provides a dielectric constant of 14.4 and smooth coverage on transition-metal dichalcogenides (TMDs). The process further incorporates a self-aligned covalently functionalized n-doping method to ensure effective contact and spacer doping, achieving uniform carrier concentration and reduced contact resistance. The resulting spacer-doped top-gate MoS2 device exhibits an on-current enhancement of 180-fold while maintaining an on/off ratio of nearly 108 under single top-gate operation. Remarkably, the single-gate configuration outperforms undoped dual-gate devices in both current level and switching characteristics. This study establishes a scalable and reliable platform for integrating high-κ dielectrics with self-aligned doping, paving the way for next-generation high-performance 2D electronics.
Subjects
2D materials
high-κ insulators
self-aligned doping
spacer doping
top-gate transistors
Publisher
John Wiley and Sons Inc
Type
journal article