CMOS Integration Schemes are the overall architectural strategies for building complementary NMOS and PMOS transistors on the same substrate — encompassing the sequence of process steps, materials choices, and structural innovations that define each technology generation.

Key Integration Decisions

• Gate Formation: Gate-first (form gate before S/D activation) vs. gate-last (replacement metal gate after S/D).
• Substrate: Bulk silicon, SOI, or strained-SOI.
• Strain Engineering: Embedded SiGe S/D (PMOS), tensile liners (NMOS), or strained channels.
• Device Architecture: Planar → FinFET → Nanosheet/GAA → CFET (evolution by node).

Why It Matters

• Performance: The integration scheme determines achievable performance (drive current, leakage, speed).
• Scalability: Each scheme has a scaling limit — driving the transition to the next architecture.
• Manufacturing: Integration complexity drives fab cost, yield, and cycle time.

CMOS Integration is the assembly blueprint for transistors — defining how all process steps fit together to build billions of complementary transistors on a chip.