Textured Semiconductor Structures for Laser Anneal Absorption
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Solution Overview
Problem
Existing semiconductor devices face challenges in efficiently absorbing laser beams for activating semiconductor materials, particularly in three-dimensional memory devices with vertical NAND strings, which affect the performance and efficiency of memory operations.
Innovation Solution
The implementation of laser beam absorption enhancement structures through textured patterns in semiconductor layers, achieved by forming alternating stacks of insulating and conductive layers, and irradiating a laser beam on unactivated semiconductor layers to convert them into activated semiconductor layers with enhanced absorption efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a planar semiconductor layer is used, then the device structure is simple, but the laser beam absorption efficiency is low
Solution Approach 1:
The patent applies surface texturing to create curved and irregular surfaces on the semiconductor layer instead of flat planar surfaces. This curvature increases the optical path length and multiple reflections of laser beams within the material, significantly enhancing absorption efficiency while maintaining a relatively simple fabrication process through chemical etching or deposition of sacrificial particles.
Solution Approach 2:
The invention transitions from a two-dimensional planar surface to a three-dimensional textured surface by introducing vertical features such as cones, pyramids, or random patterns. This dimensional change creates additional light-trapping interfaces and increases the effective surface area, thereby improving laser beam absorption without substantially complicating the device architecture.
2Productivity
If the semiconductor layer is activated without textured patterns, then the manufacturing process is simple, but the activation efficiency is low
Solution Approach 1:
The patent implements surface texturing on the semiconductor layer before the laser activation process. This preliminary action prepares the surface to maximize laser energy absorption during subsequent activation, ensuring more efficient dopant activation and crystal annealing. The texturing is formed through simple processes such as chemical etching or particle deposition, maintaining overall process simplicity while dramatically improving activation efficiency.
3Manufacturing precision
If uniform doping is applied, then the doping process is simple, but the dopant activation uniformity is poor
Solution Approach 1:
The patent creates locally varied surface textures across the semiconductor layer, with different regions having different texturing characteristics. This local quality variation ensures that each region optimally absorbs laser energy according to its specific geometry, resulting in uniform dopant activation across the entire surface despite using a uniform doping process. The texturing pattern compensates for potential non-uniformities in the doping distribution.
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
The textured patterns significantly enhance the absorption efficiency of laser beams, improving the activation of semiconductor materials and enhancing the performance of three-dimensional memory devices.
Implementation Method 1
the textured pattern enhances an absorption efficiency of the laser beam through at least one optical effect
Implementation Method 2
irradiating a laser beam on the unactivated semiconductor layer to convert the unactivated semiconductor into a semiconductor source layer
Implementation Method 3
depositing a carbon-based material layer over the matrix material layer, wherein the carbon-based material layer includes laterally-extending cracks therein; transferring a pattern of the laterally-extending cracks in the carbon-based material layer at least partially through the matrix material layer
Data Source
AI summary
A textured pattern is formed over a semiconductor structure. The textured pattern may comprise a semiconductor material including unactivated dopants, or may comprise a dielectric material overlying a semiconductor material portion including unactivated dopants. A laser anneal process can be performed by irradiating a laser beam on the textured pattern. The textured pattern enhances an absorption efficiency of the laser beam through at least one optical effect.