LDMOS Source Electrode Vias for Leakage Reduction

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Solution Overview

Problem

Lateral double-diffused MOSFETs (LDMOS) face current leakage due to the shallow position of the P-type body region, which reduces the linear drain current.

Innovation Solution

The introduction of numerous vias in the source electrode extending into the semiconductor substrate, connecting to a source contact area, helps prevent current leakage by ensuring better contact and reducing electron accumulation on the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the P-type body region is disposed at a shallower region to increase linear drain current, then the linear drain current increases, but current leakage occurs due to electron accumulation on the substrate

Engineering Contradiction:

Improvelinear drain currentVSAvoidcurrent leakage

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The source electrode is segmented into multiple separate source contacts instead of a single continuous contact. This segmentation allows each source contact to independently manage electron accumulation in its local region, preventing the formation of continuous electron paths that cause leakage while maintaining shallow body region for high current

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The source electrode structure is optimized locally at each contact point with specific via configurations and contact dimensions. Each local region can be independently tuned to prevent electron accumulation while maintaining good electrical contact, allowing the shallow body region to function effectively without causing leakage

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11670713B2LDMOS and fabricating method of the same

Publication Date: 2023.06.06 UNITED MICROELECTRONICS CORP

AI summary

An LDMOS includes a semiconductor substrate. A well is disposed within the semiconductor substrate. A body region is disposed within the well. A first gate electrode is disposed on the semiconductor substrate. A source electrode is disposed at one side of the first gate electrode. The source electrode includes a source contact area and numerous vias. The vias connect to the source contact area. The vias extend into the semiconductor substrate. A first drain electrode is disposed at another side of the first gate electrode and is opposed to the source electrode.