TRENCH POWER MOSFET WITH PLANARIZED GATE BUS

摘要

Power MOSFET's and fabrication processes for power MOSFET's use a continuous conductive gate structure within trenches to avoid device topology problems caused when a gate bus extends above a substrate. The conductive gate structure forms trench gates in an active device region and forms a gate bus in a gate bus trench. The gate bus trench connects to device trenches and can be wide to facilitate forming a contact to the gate bus. The device trenches can be narrow to maximize device density. The gate bus and/or gates can contain a metal/silicide to reduce resistance, and polysilicon can surround the metal/silicide to prevent metal atoms from penetrating the gate oxide layers. A CMP process can planarize the conductive gate structure and/or overlying insulating layers. The processes are compatible with forming self-aligned or conventional contacts in the active device region.