5. TWIN TUB FORMATION
• Provide separate optimization of the n-type and p-type transistors
• Makes it possible to optimize "Vt", "Body effect", and the "Gain" of n, p devices,
independently.
6. TWIN TUB
• Steps:
• Start with lightly doped n or p type material
• "epitaxial" or "epi" layer to prevent "latch up"
• Process sequence
• a. Tub formation
• b. Thin-Oxide construction
• c. Source & drain implantations
• d. Contact cut definition
• e. Metallization