Project

Current Status

Non-Si Atomic Layer Channel Materials: Single-crystal growth and device technology developments

Team Members

PI

Prof. Wen-Hao Chang, Professor

Dept. Electrophysics, National Yang Ming Chiao Tung University

Co-PI

Prof. Horng-Chih Lin, Professor

Institute of Electronics, National Yang Ming Chiao Tung University

Prof. Chiung-Yuan (Gene) Lin, Associate Professor

Institute of Electronics, National Yang Ming Chiao Tung University

Prof. Chang-Hsiao Chen, Assistant Professor

Dept. Electrical Engineering, National Sun Yat-Sen University

Introduction

This proposal aims at developing critical device technologies based on establishing the material synthesis technology of novel low-dimensional semiconductors. Two-dimensional (2D) materials hold great promises for surmounting the fundamental limits of conventional semiconductors and device frameworks, offering an unprecedented opportunity for the development of next-generation semiconductor technologies. To overcome the bottlenecks of 2D materials for practical device applications, this project synergizes a research team with interdisciplinary expertise of 2D materials and devices, proposing the integrated project entitled “Non-Si Atomic Layer Channel Materials: Single-crystal growth and device technology developments”. This proposal consists of five subprojects. Subproject #1 aims at developing the epitaxial growth technologies for large-area single-crystal 2D semiconductors by chemical vapor deposition (CVD). This subproject will focus on the four typical 2D semiconductors: MoS₂, MoSe₂, WS₂ and WSe₂ to achieve low defect density and high carrier mobility. For large-area (wafer-scale) growth technology, short-term goal is to achieve single-crystal growth on 2-inch wafers as a proof-of-concept demonstration, while the midterm and long-term goal of expanding the growth area larger than 4 inch will be achieved through collaboration with TIRI (Taiwan Instrument Research Institute). Subproject #2 proposes to established a CVD system in an ultra-clean and highly purified gas environment (low H₂O and O₂ concentration) to explore the growth techniques for new materials with high mobility other than the four typical 2D semiconductors, such as monochalcogenides and group-IV-element 2D materials. Subproject #3 is going to establish wafer-scale transfer techniques to realize noninvasive and ultraclean 2D materials after transfer processes. Subproject #4 will explore the strategy to achieve a low metal contact resistance based on first-principle calculations and non-equilibrium Green function theory for various metal contact configurations, which will provide a guidance for experimental realization of low contact resistance. Subproject #5 will develop novel fabrication processes for short-channel devices based on 2D materials, which can form a convenient and efficient device fabrication platform to characterize and verify the usefulness of the material growth, transfer processes and metal contacts developed by other subprojects for the ultimate device performance.

2-inch wafer scale single-crystal monolayer hBN transferred on 4-inch Si wafer.

Phase I - Achievements

By surface engineering, surface atomic steps can be formed on sapphire substrate (a,b). Using CVD growth, single-oriented MoS₂ grains can be grown of on these atomic steps (c,d). Continuing the growth, the MoS₂ grains can be stitched into a single-crystal continuous film up to 2-inch wafer size.