Flash Memory Programming Circuit Voltage Control
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Solution Overview
Problem
The existing programming methods for flash memory, particularly channel hot electron injection (CHEI), face inefficiencies in programming speed due to constant channel current limitations, leading to longer programming times and reduced performance.
Innovation Solution
A programming circuit and method that applies different voltage values to the control gate in multiple timing segments, increasing the longitudinal electric field to enhance hot electron injection efficiency without increasing channel current, thereby shortening programming time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant channel current is used for programming, then the programming operation can be performed, but the programming efficiency decreases in the latter stage and programming time increases
Solution Approach 1:
The patent applies dynamics by transitioning from constant channel current to dynamically adjusted control gate voltage. The control gate voltage is increased in multiple stages during the programming process, allowing the longitudinal electric field to strengthen over time and maintain high electron injection efficiency throughout the programming operation, thereby improving productivity and reducing programming time.
Solution Approach 2:
The patent implements parameter changes by adjusting the control gate voltage in multiple stages rather than maintaining a constant channel current. By changing the voltage parameter dynamically during programming, the longitudinal electric field is enhanced, which improves hot electron injection efficiency and solves the declining efficiency problem in the latter programming stage.
2Productivity
If channel current is increased to improve injection efficiency, then electron injection rate increases, but the current density exceeds manufacturing process limits
Solution Approach 1:
The patent changes the controlling parameter from channel current to control gate voltage. By adjusting the voltage parameter instead of increasing current, the longitudinal electric field is strengthened to improve electron injection efficiency without exceeding the manufacturing process limits for channel current density.
Solution Approach 2:
The control gate voltage acts as an intermediary parameter to achieve the desired electron injection efficiency. Instead of directly increasing channel current, the patent uses control gate voltage as a mediator to indirectly enhance the longitudinal electric field and improve injection efficiency while staying within manufacturing constraints.
3Reliability
If multiple programming operations are performed to complete programming, then the flash memory can be programmed, but the programming time and operational complexity increase
Solution Approach 1:
The patent applies periodic action through multi-stage voltage adjustment of the control gate. The programming process is divided into stages with progressively increased voltages, creating a structured periodic action that ensures reliable programming completion while reducing the total time required compared to traditional multiple programming operations.
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
Improves the efficiency of the latter stage programming process, reducing total programming time and enhancing the performance of flash memory without increasing channel current.
Implementation Method 1
The programming of the flash memory is to change the threshold voltage of the storage cell by injecting electrons into the floating gate or pulling the electrons out of the floating gate
Implementation Method 2
one is channel programming based on F-N tunneling
Implementation Method 3
The other is drain terminal injection based on CHIE (channel hot electron injection)
Implementation Method 4
applying different voltage values to the control gate in multiple timing segments, increasing the longitudinal electric field to enhance hot electron injection efficiency
Data Source
AI summary
The present invention relates to a programming circuit and a programming method of a flash memory, the programming circuit includes a programming transistor and a storage cell connected in series, a gate of the programming transistor is connected to a word line, a gate of the storage cell is connected to a control gate, one end of the programming transistor is connected to a bit line, the other end of the programming transistor is connected to one end of the storage cell, and the other end of the storage cell is connected to a source line. By programming the flash memory by the programming circuit and method of the present invention, the efficiency of latter stage programming can be improved without increasing channel current, thereby improving the efficiency of the entire programming process, shortening the total programming time, and improving the performance of the flash memory.