Toward Low-Temperature Solid-Source Synthesis of Monolayer MoS₂.

Area of Science:

• Materials Science
• Semiconductor Physics
• Nanotechnology

Background:

• Two-dimensional (2D) semiconductors offer potential for heterogeneous integration with silicon.
• High chemical vapor deposition (CVD) growth temperatures of 2D materials limit compatibility with silicon manufacturing.
• A need exists for low-temperature synthesis methods for 2D semiconductors.

Purpose of the Study:

• To demonstrate direct CVD solid-source precursor synthesis of continuous monolayer (1L) MoS₂ films.
• To achieve growth within the thermal budget required for back-end-of-the-line silicon technology compatibility.
• To evaluate the performance of synthesized MoS₂ films in transistors.

Main Methods:

• Direct CVD solid-source precursor synthesis of MoS₂.
• Growth temperature optimized to 560 °C with a 50 min deposition time.
• Fabrication and characterization of field-effect transistors (FETs) with 100 nm channel lengths.

Main Results:

• Continuous monolayer MoS₂ films were synthesized at 560 °C within a 2 h thermal budget.
• Transistors exhibited high on-state current (∼140 μA/μm at 1 V) for 1L MoS₂ grown below 600 °C.
• Effective electron mobility of 29 ± 5 cm² V^-1 s^-1 was achieved, comparable to higher-temperature grown films.

Conclusions:

• Low-temperature CVD synthesis of high-quality MoS₂ is feasible.
• The developed method meets thermal budget requirements for silicon manufacturing integration.
• This work paves the way for thermal-budget-compatible 2D semiconductors in heterogeneous integration.