Semiconductor Memory Hot Carrier Injection Programming
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Solution Overview
Problem
The existing semiconductor memory devices face challenges in reducing the width of threshold voltage distribution after an erase operation, leading to increased time for program operations due to velocity differences between memory cells with varying threshold voltages.
Innovation Solution
Implementing a soft program operation using the hot carrier injection (HCI) method to program memory cells, where a control voltage is applied to adjacent memory cells to inject hot carriers, thereby increasing the threshold voltage and narrowing the distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a soft program operation is performed using the FN tunneling method to program memory cells simultaneously, then the program operation can be completed, but the threshold voltage distribution width increases and the program velocity difference between memory cells persists
Solution Approach 1:
The patent changes the programming method from FN tunneling to hot carrier injection (HCI), which fundamentally alters the physical mechanism of charge injection. This parameter change in the programming approach enables better control over threshold voltage distribution by injecting carriers through a different physical process that reduces velocity differences between memory cells with varying threshold voltages
Solution Approach 2:
The patent substitutes the FN tunneling mechanism with hot carrier injection mechanism. Instead of relying on quantum tunneling through a barrier, the system uses hot carrier injection where carriers are injected into the floating gate through a different physical process, achieving better threshold voltage distribution control
2Productivity
If memory cells with different threshold voltages are programmed simultaneously, then the program operation can proceed in parallel, but velocity difference occurs between memory cells leading to increased program time
Solution Approach 1:
The patent changes the programming mechanism from FN tunneling to hot carrier injection, which modifies how charge is injected into memory cells. This parameter change in the physical process enables simultaneous programming of memory cells with different threshold voltages without significant velocity differences, reducing overall program time while maintaining parallel operation
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 HCI method effectively reduces the width of the threshold voltage distribution, improving the efficiency of subsequent program operations by ensuring all memory cells reach a target threshold voltage, thereby reducing the time required for programming.
Implementation Method 1
a soft program operation using a hot carrier injection HCI method... a control voltage is applied to adjacent memory cells to inject hot carriers, thereby increasing the threshold voltage
Implementation Method 2
A memory cell is programmed though an FN tunneling method when a program operation of the semiconductor memory device is performed. In case that high voltage is applied to a control gate of the memory cell in the program operation, electrons are charged in a floating gate of the memory cell
Data Source
AI summary
A semiconductor memory device and a method of operating the same are disclosed. The semiconductor memory device includes a memory cell array configured to include memory cells, a peripheral circuit configured to perform an erase operation and a soft program operation and a control circuit configured to control the peripheral circuit so that the memory cells are programmed though a hot carrier injection HCI method when the soft program operation is performed.