Soft Breakdown Antifuse Memory Cell Low Power
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional non-volatile memory (NVM) cells require high power for programming and reading, especially due to the need for hard breakdown of the gate oxide, which results in high voltage drops and inefficient signal levels.
Innovation Solution
The implementation of an antifuse-based NVM cell using a field-effect transistor that operates with a modest programming voltage under 5.5 volts and achieves soft breakdown in the thin gate oxide, allowing for low-power operation through a local sense transistor that amplifies the programming current for column sense amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hard breakdown of gate oxide is used for programming, then reliable data storage is achieved, but programming power consumption increases significantly
Solution Approach 1:
The patent changes the breakdown mode parameter from hard breakdown to soft breakdown, and adjusts the gate oxide thickness to 50-150nm. This parameter change allows the gate oxide to achieve a high-resistance state (10^6 to 10^9 ohms) that provides reliable data storage without requiring the high current (hundreds of microamperes) needed for hard breakdown, thus reducing programming power consumption to a few microamperes
Solution Approach 2:
Instead of applying excessive voltage and current to achieve hard breakdown, the patent applies partial action by using moderate programming voltage (under 5.5V) and current (a few microamperes) to achieve soft breakdown. This partial action is sufficient to create the high-resistance state needed for data storage while avoiding the excessive power consumption of hard breakdown
2Power
If hard breakdown is used to achieve low resistance for reading, then reasonable sense current is obtained, but read voltage requirement increases to >2.5-3.3V
Solution Approach 1:
The patent changes the resistance parameter of the gate oxide from low resistance (hard breakdown) to high resistance (10^6 to 10^9 ohms). This parameter change enables reading operation at low voltage (0.5-1V) because the high resistance creates sufficient voltage drop and signal level even with low sense current, eliminating the need for high read voltage (>2.5-3.3V)
3Measurement precision
If high sense current (1-10 μA) is used for reading, then adequate signal level is achieved, but voltage drop over high resistance requires >2.5-3.3V
Solution Approach 1:
The patent changes the gate oxide resistance parameter to high resistance (10^6 to 10^9 ohms), which fundamentally alters the voltage-current relationship. This allows adequate signal level to be achieved at low voltage (0.5-1V) because the high resistance amplifies the voltage signal even with low sense current, eliminating the need for high read voltage that would be required with low resistance
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 reduces programming current from hundreds of microamperes to a few microamperes and allows for reading with voltages as low as 0.5-1 volt, making the technology suitable for low-power applications like RFID memory without requiring hard breakdowns.
Implementation Method 1
Only a soft breakdown is needed in the thin gate oxide because a local sense transistor is used during read operations to detect the programming and amplify it for column sense amplifiers
Data Source
AI summary
A non-volatile memory cell using two transistors, a bit select and a sense device and an antifuse device. The antifuse device is implemented with a field-effect transistor operated to behave like an antifuse when the cell is selected and a modest programming voltage under 5.5 volts and a current under 5-μA is applied. Only a soft breakdown is needed in the thin gate oxide because a local sense transistor is used during read operations to detect the programming and amplify it for column sense amplifiers. Reading also only requires low voltages of about one volt.