Understanding Power MOSFET Structure

Source Metal: Top metal layer for current collection and distribution
n+ Source Regions: Heavily doped regions for carrier injection
p-Body Region: Creates the channel for current flow
n- Drift Region: Supports voltage blocking capability
n+ Substrate: Provides low resistance path to drain
Drain Metal: Bottom metal contact for current flow

Power MOSFETs are crucial components in modern power electronics, designed to handle high voltages and currents. Let’s explore their unique structural features that enable efficient power handling capabilities.

Basic Structure Overview

    Source Metal
        ║
    ╔═══╩═══╗
    ║ n+ ║ n+ ║      Source
════╝     ╚════
    p+    p      Body
    │
    │  n-        Drift Region
    │
    │
════════════════ n+ Substrate
    ║
    ╨  Drain Metal

Cross-sectional view of a typical Power MOSFET

Vertical Structure

Unlike regular MOSFETs, power MOSFETs employ a vertical structure where current flows from top (source) to bottom (drain), maximizing current handling capacity.