Domed Floating Gate Reduces Leakage in Nonvolatile Memory
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nonvolatile memory devices with floating-gate structures suffer from high inter-poly dielectric leakage current due to field crowding effects, leading to small program windows, poor endurance, and reduced data retention when manufactured using below 20 nm technology nodes.
Innovation Solution
A method is developed to form a nonvolatile memory device with a conductive layer having a top surface with a minimum fitted curvature radius, which is converted into a domed surface to reduce edge effects and enhance inter-poly dielectric integrity, involving steps such as trench isolation, chemical-mechanical polishing, and low-temperature oxidation processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional floating-gate structure is used in below 20 nm technology nodes, then the device can be manufactured with standard processes, but high inter-poly dielectric leakage current occurs due to field crowding effects at the edges of the floating gate
Solution Approach 1:
The patent applies curvature by forming a domed surface on the conductive layer (floating gate) instead of using a flat top surface. This curvature redistributes the electric field, reducing field crowding at the edges and thereby decreasing inter-poly dielectric leakage current while maintaining compatibility with standard manufacturing processes
2Ease of manufacture
If the floating gate has sharp edges, then the manufacturing process is simpler, but field crowding effects increase causing high leakage current and poor endurance
Solution Approach 1:
The patent introduces a domed surface configuration on the floating gate through oxidation processes, which eliminates sharp edges and reduces field crowding effects. This curvature modification decreases the harmful field concentration at edges, reducing leakage current and improving device endurance without significantly complicating the manufacturing process
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 approach effectively reduces inter-poly dielectric leakage current, improving program window size and data retention in nonvolatile memory devices by minimizing field crowding and optimizing the curvature of the conductive layer's surface.
Implementation Method 1
low-temperature oxidation processes
Data Source
AI summary
A method for making a nonvolatile memory device includes the following steps. A conductive structure is formed, wherein the conductive structure has a first top portion. The first top portion is converted into a second top portion having a domed surface.