Polycrystalline Channel Structure for NAND Select Gate Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor storage devices face challenges in achieving improved reliability of operations, particularly in maintaining efficient memory cell performance and controlling impurity diffusion within polycrystalline semiconductor films.
Innovation Solution
The semiconductor storage device incorporates a laminated body with conductive layers and insulating layers, featuring a polycrystalline semiconductor film with distinct sections of varying average grain diameters. This design allows for controlled impurity diffusion and enhanced GIDL generation, improving the reliability of memory cell operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform polycrystalline semiconductor film is used throughout the column, then the manufacturing process is simple, but impurity diffusion cannot be controlled and GIDL generation is insufficient
Solution Approach 1:
The polycrystalline semiconductor film is divided into two sections with different average grain diameters: a first section with smaller grain diameter near the upper conductive layer to suppress impurity diffusion and generate GIDL, and a second section with larger grain diameter in the lower portion for stable electrical characteristics. This local differentiation resolves the contradiction by optimizing each region for its specific function.
Solution Approach 2:
The polycrystalline semiconductor film is segmented into multiple sections along the column height, with each section having controlled grain diameter characteristics. This segmentation allows independent optimization of impurity diffusion control in the upper section and electrical stability in the lower section, improving overall reliability without requiring completely new materials.
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 solution effectively improves the reliability of semiconductor storage devices by ensuring efficient GIDL generation and proper turn-on/off functionality of select gates, thereby enhancing overall device performance.
Implementation Method 1
When the average grain diameter of the first polycrystalline semiconductor film 42a is smaller than the average grain diameter of the second polycrystalline semiconductor film 42b, excessive diffusion of impurities from the second polycrystalline semiconductor film 42a to the second polycrystalline semiconductor film 42b can be suppressed.
Implementation Method 2
When the average grain diameter of the first polycrystalline semiconductor film 42a is smaller than the average grain diameter of the second polycrystalline semiconductor film 42b, excessive diffusion of impurities from the second polycrystalline semiconductor film 42a to the second polycrystalline semiconductor film 42b can be suppressed. As a result, GIDL can be effectively generated during erase operations.
Data Source
AI summary
According to one embodiment, a semiconductor storage device has a laminated body comprising conductive layers alternating with insulating layers in a first direction. A column extends into the laminated body and includes a first polycrystalline semiconductor film extending along the column in the first direction and a first insulating film extending along the column in the first direction. The first insulating film is between the conductive layers and the first polycrystalline semiconductor film. The first polycrystalline semiconductor film includes a first section corresponding in position along the first direction to an uppermost conductive layer among the conductive layers in the laminated body and a second section that is between the first section and a substrate in the first direction. An average grain diameter of the first section is smaller than an average grain diameter of the second section.