Semiconductor Memory Device Silicon Germanium Layer Design
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Solution Overview
Problem
The challenge in increasing the integration density of semiconductor memory devices is hindered by the difficulty in reducing linewidths, which requires advanced and costly lithography technologies, and existing structures do not efficiently reduce chip size while maintaining reliability.
Innovation Solution
A semiconductor memory device design that includes a substrate with a cell and peripheral region, featuring lower electrodes, a dielectric layer, a metal-containing layer, a silicon germanium layer, conductive pads, and upper electrode contact plugs, where the silicon germanium layer extends beyond the conductive pads to reduce chip size and prevent short circuits, and a conductive pad with high conductivity is used to reduce electric resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lithography technology is advanced to reduce linewidths, then integration density is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent transitions from planar 2D electrode arrangements to a 3D stacked configuration with lower electrodes, dielectric layers, and upper electrodes vertically arranged. This vertical stacking enables higher integration density without requiring further linewidth reduction, thereby avoiding the need for advanced lithography technologies.
Solution Approach 2:
The patent implements a nested structure where upper electrodes are positioned within the vertical projection area of lower electrodes, with conductive plugs connecting them through intermediate conductive layers. This nested arrangement maximizes space utilization and achieves high integration density without demanding stricter linewidth control.
2Area of stationary object
If chip size is reduced, then integration density is improved, but reliability may deteriorate due to shorter distances and increased stress
Solution Approach 1:
The patent introduces a graded silicon germanium layer with varying composition ratios between the lower electrode and upper electrode. This gradual transition in material composition locally adjusts stress distribution, preventing stress concentration that would otherwise occur in miniaturized structures, thereby maintaining reliability while reducing chip size.
Solution Approach 2:
The patent employs a composite structure combining silicon germanium layers with different composition ratios, dielectric materials, and conductive materials. This composite approach allows optimization of both mechanical stress management and electrical performance, ensuring reliability in compact chip designs.
3Area of stationary object
If silicon germanium layer is made thinner to reduce chip size, then integration density is improved, but electrical resistance may increase
Solution Approach 1:
The patent modifies the composition ratio parameter of the silicon germanium layer, creating a gradient from lower germanium content near the lower electrode to higher germanium content near the upper electrode. This parameter optimization balances stress management and electrical conductivity, maintaining low resistance even in thinner layer configurations.
Solution Approach 2:
The patent combines silicon germanium layers with intermediate conductive layers and conductive plugs to create a composite conductive path. This composite structure compensates for the increased resistance in thinner silicon germanium layers, ensuring overall low resistance while maintaining reduced chip dimensions.
Data Source
AI summary
A semiconductor memory device is provided. The device includes a substrate including a cell region and a peripheral region; a plurality of lower electrodes disposed on the substrate in the cell region; a dielectric layer disposed on the plurality of lower electrodes; a metal containing layer disposed on the dielectric layer; a silicon germanium layer disposed on and electrically connected to the metal containing layer; a conductive pad disposed on and electrically connected to the silicon germanium layer; and an upper electrode contact plug disposed on and electrically connected to the conductive pad; The conductive pad extends from the upper electrode contact plug towards the peripheral region in a first direction, and the silicon germanium layer includes an edge portion that extends past the conductive pad in the first direction.