Floating Contact MOS Evaluation Element for DC Variation Isolation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for evaluating the DC characteristics of MOS transistors fail to separate the variations caused by stress from those caused by parasitic resistance, making it difficult to analytically estimate the impact of contact formation on transistor performance.

Innovation Solution

A semiconductor evaluation element with floating contacts between the gate and measurement contacts, allowing for the separation of contact position and number effects on DC characteristics by varying the contact width to transistor width ratio and distance, enabling precise measurement of DC variations due to contact stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If contacts are formed on diffusion layers to measure DC characteristics, then current characteristics can be evaluated, but stress applied to the channel region is reduced and parasitic resistance is introduced, affecting measurement accuracy

Engineering Contradiction:

ImproveDC characteristic measurement accuracyVSAvoidparasitic resistance and stress reduction

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent divides the contact structure into two distinct types: measurement contacts for electrical connection and floating contacts for stress application. This segmentation allows the measurement contacts to provide necessary electrical access while the floating contacts independently apply stress to the channel region without introducing parasitic resistance into the measurement path, thereby resolving the contradiction between measurement accuracy and harmful effects.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The floating contacts serve as an intermediary element that applies stress to the channel region without being part of the current measurement path. By introducing this intermediate structure, the patent enables stress application while preventing the measurement contacts from introducing parasitic resistance and stress reduction effects, thus improving measurement accuracy without the harmful side effects.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If multiple evaluation elements with different contact positions are prepared to separate stress effects from parasitic resistance effects, then analytical estimation becomes possible, but device complexity and measurement time increase

Engineering Contradiction:

Improveseparation of stress effects and parasitic resistance effectsVSAvoidnumber of evaluation elements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the contact functionality into measurement contacts and floating contacts within a single evaluation element. This allows both stress application and electrical measurement to occur simultaneously in one structure, eliminating the need for multiple separate evaluation elements with different contact positions. The segmentation enables analytical estimation while reducing device complexity and measurement time.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The evaluation element is designed with multi-functionality: measurement contacts provide electrical connection for current measurement, while floating contacts apply stress to the channel region. This universal design allows a single evaluation element to perform both stress application and accurate measurement functions that previously required multiple separate elements, thereby reducing complexity while maintaining measurement precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If contact width and position are varied to study their effects on DC characteristics, then understanding of contact stress impact is improved, but the number of measurement configurations required increases

Engineering Contradiction:

Improveability to study contact position and width effectsVSAvoidmeasurement time for multiple configurations

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent introduces adjustable floating contacts that can be positioned at different locations along the diffusion layer and have variable widths. This dynamic configurability allows systematic variation of contact position and width parameters within a single evaluation element, enabling comprehensive study of their effects on DC characteristics without requiring multiple separate measurement configurations, thus reducing measurement time while maintaining adaptability.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS7764077B2Semiconductor device including semiconductor evaluation element, and evaluation method using semiconductor device

Publication Date: 2010.07.27 RENESAS ELECTRONICS CORP

AI summary

Provided are a semiconductor evaluation element capable of analytically estimating the amount of DC variation of a MOS transistor which is caused by formed contacts, and an evaluation circuit and an evaluation method using the semiconductor evaluation element. The semiconductor evaluation element such as a MOS transistor includes: a gate; diffusion layers; measurement contacts; and floating contacts. The diffusion layers are formed on both sides of the gate and serve as a source and a drain. The measurement contacts are provided in positions apart from the gate on the diffusion layers. The floating contacts are provided between the gate and the measurement contacts to connect electrically isolated metal layers with the diffusion layers.