Dynamic Precharge Voltage Control for Memory Disturbance Reduction
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Solution Overview
Problem
Memory devices experience disturbances during program operations due to hot carrier injection and Fowler-Nordheim stress, leading to threshold voltage changes in memory cells, which can result in data retention issues and reduced device reliability.
Innovation Solution
The memory device incorporates a control logic that adjusts the precharge voltage and dummy voltage applied to the common source line and dummy word lines based on the program voltage magnitude, optimizing the duration and magnitude of these voltages across multiple program loops to minimize disturbance phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed precharge voltage is applied to the common source line during program operation, then the program operation can be performed, but disturbance phenomena occur due to hot carrier injection and Fowler-Nordheim stress
Solution Approach 1:
The precharge voltage applied to the common source line is dynamically adjusted based on the program voltage magnitude. During program operations, the precharge voltage is set to a first level when the program voltage is at a first level, and adjusted to a second level when the program voltage changes to a second level. This dynamic adjustment reduces disturbance phenomena caused by hot carrier injection and Fowler-Nordheim stress while maintaining reliable program operation.
Solution Approach 2:
The invention changes the voltage parameter of the common source line from a fixed value to a variable value that depends on the program voltage magnitude. By modifying the precharge voltage parameter in response to program voltage changes, the system minimizes threshold voltage shifts in memory cells caused by disturbance phenomena, thereby improving data retention and reliability.
2Reliability
If the precharge voltage magnitude and application time are kept constant, then the control is simple, but the disturbance phenomenon cannot be minimized
Solution Approach 1:
The control logic monitors the program voltage magnitude and adjusts the precharge voltage applied to the common source line accordingly. This feedback mechanism ensures that the precharge voltage is optimized for each program operation condition, minimizing disturbance phenomena while maintaining manageable control complexity through automated adjustment based on program voltage levels.
3Object-affected harmful factors
If a higher precharge voltage is applied continuously, then the disturbance phenomenon may be reduced, but the energy consumption increases
Solution Approach 1:
Instead of applying a continuously high precharge voltage, the invention adjusts the precharge voltage parameter dynamically based on the program voltage magnitude. The precharge voltage is set to appropriate levels matching the program voltage conditions, which reduces disturbance phenomena effectively while avoiding the excessive energy consumption that would result from continuously applying a high precharge voltage.
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
This approach effectively reduces disturbances caused by hot carrier injection and Fowler-Nordheim stress, improving data retention and reliability by dynamically controlling voltage parameters during program operations.
Implementation Method 1
Memory devices experience disturbances during program operations due to hot carrier injection and Fowler-Nordheim stress
Implementation Method 2
Memory devices experience disturbances during program operations due to hot carrier injection and Fowler-Nordheim stress
Data Source
AI summary
Provided herein may be a memory device and a method of operating the same. The memory device may include a plurality of memory cells coupled between a common source line and a bit line, a peripheral circuit configured to perform a plurality of program loops, each including a program voltage application operation of applying a program voltage to a selected memory cell and a verify operation of verifying a program state of the selected memory cell, and a control logic configured to control, at the program voltage application operation, the peripheral circuit to apply a precharge voltage to the common source line and change at least one of a magnitude of the precharge voltage and a time during which the precharge voltage is applied, depending on a magnitude of the program voltage.