Buried Gate Electrode Structure for GIDL and Threshold Control

Solution Overview

Problem

Existing semiconductor devices with buried gates face challenges in controlling threshold voltage and reducing Gate Induced Drain Leakage (GIDL) characteristics, which affect their high-performance operation.

Innovation Solution

A semiconductor device design that includes a trench in a substrate with a first gate electrode containing a trap passivation material filling the lower portion of the trench, and a second gate electrode with the same material filling the middle portion, to improve electrical characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a metal gate electrode is used for high performance transistors, then transistor performance is improved, but threshold voltage control and GIDL characteristics deteriorate

Engineering Contradiction:

Improvetransistor performanceVSAvoidthreshold voltage control and GIDL characteristics

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The gate electrode is divided into two distinct segments: a first gate electrode made of a first metal material and a second gate electrode made of a second metal material. This segmentation allows each segment to contribute different properties, improving both transistor performance and electrical characteristics while mitigating the drawbacks of using a single metal gate material.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention employs a composite gate electrode structure combining two different metal materials. The first metal material and second metal material are selected to have different work functions and electrical properties, creating a composite structure that optimizes both drive current and threshold voltage control, while reducing GIDL effects through the complementary properties of the two materials.

Inventive Principle:

Principle #40Composite materials

2Device complexity

If a single gate electrode structure is used, then device complexity is reduced, but electrical characteristics and performance deteriorate

Engineering Contradiction:

Improvegate electrode structureVSAvoidelectrical characteristics

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The gate electrode is divided into two distinct segments: a first gate electrode made of a first metal material and a second gate electrode made of a second metal material. This segmentation allows each segment to contribute different properties, improving both transistor performance and electrical characteristics while mitigating the drawbacks of using a single metal gate material.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the gate electrode are assigned different metal materials with specific properties optimized for their local function. The first metal material may be optimized for one aspect of performance while the second metal material addresses another aspect, allowing each local region to contribute its optimal properties to the overall device performance.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250194171A1Semiconductor device

Publication Date: 2025.06.12 SK HYNIX INC

AI summary

A semiconductor device includes a trench formed in a substrate; a first gate electrode filling a lower portion of the trench, and the first gate electrode containing a trap passivation material; and a second gate electrode formed over the first gate electrode, and the second gate electrode containing the trap passivation material. The reliability of semiconductor devices may be improved by applying a gate electrode containing a trap passivation material. The resistance of a word line may be reduced by applying a gate electrode containing a metal material. The gate-induced drain leakage (GIDL) may be reduced by adjusting the work functions of the upper and lower gate electrodes.