Vertical Channel Transistor String Body Connection

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Solution Overview

Problem

The integration of semiconductor memory devices is limited by the floating of vertical channels in transistors, leading to hole accumulation and leakage currents, which deteriorate data retention properties.

Innovation Solution

A semiconductor device with active pillars and a string body connection portion that connects channel regions of adjacent pillars, using a conductivity type matching the channel region, and an insulating gap-fill pattern to prevent channel floating, along with a voltage generation portion to manage voltages applied to the string body connection and substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a vertical transistor with vertically spaced source and drain regions is used, then integration density is improved, but the channel region becomes floating leading to hole accumulation and leakage current

Engineering Contradiction:

Improveintegration densityVSAvoiddata retention property

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

A string body connection portion is introduced as an intermediary element to connect the channel regions of adjacent vertical transistors. This connection portion provides a conductive pathway that prevents the channel from floating, thereby eliminating hole accumulation and leakage current while preserving the high integration density achieved through vertical transistor architecture

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Adjacent channel regions are merged through the string body connection portion, creating a continuous conductive structure. This merging approach allows multiple vertical transistors to share a common potential reference, preventing floating effects without requiring individual isolation structures for each transistor

Inventive Principle:

Principle #5Merging (Combining)

2Device complexity

If the channel region is left floating to simplify structure, then device complexity is reduced, but leakage current increases and data retention deteriorates

Engineering Contradiction:

Improvestructure simplicityVSAvoidleakage current

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The string body connection portion serves as a mediator that connects adjacent channel regions, providing a controlled conductive path. This intermediary structure prevents harmful floating effects and leakage currents while adding minimal structural complexity to the device

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8987811B2Semiconductor devices including a vertical channel transistor and methods of fabricating the same

Publication Date: 2015.03.24 SAMSUNG ELECTRONICS CO LTD

AI summary

According to example embodiments, a semiconductor device includes a plurality of active pillars protruding from a substrate. Each active pillar includes a channel region between upper and lower doped regions. A contact gate electrode faces the channel region and is connected to a word line. The word line extends in a first direction. A bit line is connected to the lower doped region and extends in a second direction. The semiconductor device further includes a string body connection portion that connects the channel region of at least two adjacent active pillars of the plurality of active pillars.