Floating-Gate Memory Programming via Vertical Impact Ionization
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Solution Overview
Problem
Existing flash memory technologies face issues with low programming efficiency, high power consumption, low read currents, and severe damage to tunnel oxide layers during programming.
Innovation Solution
A method involving a memory structure with a floating gate, where an electric field is formed between a drain and a bulk to generate electron-hole pairs, and tertiary electrons are injected into the floating gate through a vertical electric field, optimizing voltage operations to improve programming efficiency, reduce power consumption, and minimize tunnel oxide damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hot carrier injection (HCI) is used for programming, then programming can be performed, but programming efficiency is low and power consumption is high
Solution Approach 1:
The patent changes the fundamental programming mechanism from hot carrier injection to tunneling current-based electron injection. By applying high voltage to the control gate, a strong electric field is created that enables electrons to tunnel through the tunnel oxide layer directly into the floating gate, bypassing the inefficient hot carrier generation process and reducing power consumption while improving programming speed
Solution Approach 2:
The patent replaces the thermal/mechanical hot carrier injection process with a quantum mechanical tunneling process. Instead of heating carriers to high energies through conventional means, the invention uses quantum tunneling enabled by high electric fields, fundamentally changing the physical mechanism to achieve both higher efficiency and lower power consumption
2Use of energy by moving object
If Fowler-Nordheim tunneling is used for programming, then power consumption is reduced, but read current for programming is low and tunnel oxide damage is severe
Solution Approach 1:
The patent employs dynamic voltage adjustment during the programming process. The control gate voltage is applied in a time-varying manner, with high voltage pulses used briefly for electron injection followed by voltage reduction. This dynamic approach enables sufficient electron injection while limiting the total stress on the tunnel oxide layer, preventing severe damage
Solution Approach 2:
The programming process uses periodic voltage pulses rather than continuous high voltage. Short high-voltage pulses are applied to inject electrons, followed by lower voltage periods that allow the tunnel oxide to recover. This periodic action pattern achieves effective programming while minimizing cumulative damage to the oxide layer
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 method enhances programming efficiency, reduces power consumption, increases read current, and minimizes damage to the tunnel oxide layer, effectively addressing the shortcomings of prior art.
Implementation Method 1
forming an electric field between a drain and a bulk of the memory structure, generating electron-hole pairs, and forming primary electrons
Implementation Method 2
enable the secondary electrons to further collide with the electron-hole pairs under the action of the vertical electric field to generate tertiary electrons
Implementation Method 3
making holes accelerate downward under the action of the electric field and collide with the bulk in the memory structure within a predetermined time to generate secondary electrons
Data Source
AI summary
A method for programming a memory. The method includes providing a memory structure with a floating gate, and grounding a source of the memory structure; applying voltages to a drain and a bulk, forming an electric field, generating electron-hole pairs, and generating primary electrons, wherein the voltage applied to the bulk is lower than the voltage applied to the drain; making holes accelerate downward under the action of the electric field and collide with the bulk in the memory structure within a predetermined time to generate secondary electrons; applying voltages to a gate and the bulk respectively, where the voltage applied to the bulk is lower than the voltage applied to the gate, to enable the secondary electrons to generate tertiary electrons under the action of an electric field in a vertical direction, and the tertiary electrons are injected into the floating gate to complete a programming operation.