2D Semiconductors Inch Forward: Samsung and Intel-CEA Leti Advance TMD Integration for Post-Silicon Chips

Transition metal dichalcogenides (TMDs) like MoS₂ and WSe₂ are inching closer to replacing silicon in next-generation transistors, with Samsung and Intel-CEA Leti presenting new integration breakthroughs at recent conferences.

Why 2D Materials?

TMDs offer key advantages over silicon at atomic scales:

• No out-of-plane dangling bonds: Less interface scattering
• Better carrier mobility: In ultra-thin channels where silicon degrades
• Continued scaling potential: When silicon's benefits diminish

Samsung's Approach

Samsung researchers deposited a thin passivating oxide on MoS₂ channels that:

1. Protects the 2D material from plasma damage and contamination
2. Is permeable to oxygen — diffusing into TMD edges
3. Creates strong bonds between oxidized regions, substrate, and channel
4. Prevents delamination — solving a critical adhesion problem

They also demonstrated selective growth techniques that reduce time and thermal budget requirements.

Intel-CEA Leti's "Channel-Last" Approach

CEA-Leti and Intel used a strategy that preserves most of the traditional silicon GAA process flow:

1. Build Si/SiGe multilayer stack
2. Process through replacement metal gate and self-aligned contact etch
3. Remove existing channels and fill with ALD MoS₂ (nFETs) and WSe₂ (pFETs)
4. Add gate dielectric

Remaining Challenges

• CVD growth requires >600°C (can damage dielectrics)
• Layer transfer techniques difficult to scale commercially
• Thermal expansion mismatch causes delamination
• High energy barriers at contacts

Outlook

Progress is described as "steady but fundamental questions remain." 2D semiconductors represent the most promising path beyond silicon for ultra-scaled transistors, but commercial viability is still years away.