Pillar-Shaped Semiconductor Device with Oxidation-Resistant Mask
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Solution Overview
Problem
There is a demand for pillar-shaped semiconductor devices with higher density and performance that can be produced at lower costs, but reducing the sectional diameter of semiconductor pillars for increased density makes them prone to damage and difficult to produce efficiently.
Innovation Solution
A method for producing pillar-shaped semiconductor devices involves forming a semiconductor pillar on a substrate with a semiconductor-pillar base part and an oxidation-resistant mask material layer, oxidizing the substrate to create recessed oxide insulating layers, and using multiple mask layers for etching and oxidation-resistant functions to stabilize the pillar and reduce production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the sectional diameter of semiconductor pillars is reduced to increase density, then device density is improved, but the pillars become more prone to damage and production difficulty increases
Solution Approach 1:
The patent applies preliminary action by forming a semiconductor-pillar base part before forming the pillar itself. This base part is created through selective oxidation of the substrate, establishing a stable foundation that prevents pillar damage during subsequent processing steps. The base part is formed in advance to support the pillar structure, particularly important when pillars have reduced diameters for high density.
Solution Approach 2:
The semiconductor-pillar base part acts as an intermediary between the substrate and the semiconductor pillar. This intermediate structure provides mechanical support and stability to the pillar, reducing the risk of damage during fabrication and operation. The base part mediates the stress and structural requirements, allowing thin pillars to maintain reliability while achieving high density.
2Manufacturing precision
If multiple mask layers are used for etching and oxidation-resistant functions, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing mask material layers that perform multiple functions simultaneously. The oxidation-resistant mask material layer serves both as an etching mask and as a protective layer during oxidation processes. This multi-functionality reduces the total number of separate mask layers needed, simplifying the overall process while maintaining high manufacturing precision for pillar formation.
Solution Approach 2:
The patent merges the functions of etching mask and oxidation-resistant layer into a single integrated mask structure. Instead of using separate layers for etching protection and oxidation resistance, the invention combines these functions in one mask material layer system, reducing process complexity while achieving precise pillar formation through the coordinated action of the base part and mask layers.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the formation of high-density pillar-shaped semiconductor devices with improved stability and reduced production costs by using recessed oxide insulating layers and multiple mask layers to protect the semiconductor pillars during processing.
Implementation Method 1
an oxidation-resistant mask material layer surrounding a top portion and a side surface of the semiconductor pillar
Implementation Method 2
oxidizing an entirety or a bottom portion of the semiconductor-pillar base part and a surface layer portion of the semiconductor substrate in a region around the semiconductor-pillar base part, to form an oxide insulating layer
Data Source
AI summary
A Si substrate is etched through a first mask material layer formed on the Si substrate and serving as a mask, to form a Si pillar on a Si substrate. Subsequently, a second mask material layer formed so as to surround the side surface of the Si pillar is used as a mask to form a Si-pillar base part surrounding the Si pillar. Subsequently, the first and second mask material layers are used as masks to form a SiO2 layer so as to occupy the whole section of the Si-pillar base part and connect to the Si substrate positioned in a region around the Si-pillar base part. Recessed portions are formed in the upper and lower regions of the SiO2 layer. Subsequently, on the SiO2 layer, an SGT is formed so as to include a gate insulating HfO2 layer surrounding the Si pillar, a gate conductor TiN layer, N+ layers serving as the source or drain within the Si pillar, and a Si pillar serving as the channel between the N+ layers.