Wordline Drive Circuit Using Ring Oscillation to Reduce GIDL
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Solution Overview
Problem
The miniaturization of memory cells leads to thinner gate oxide layers in N-type transistors, causing Gate Induced Drain Leakage (GIDL) due to the wordline signal being in a high-level state for extended periods, which negatively affects the reliability and service life of the transistors and memory cells.
Innovation Solution
A wordline driving circuit incorporating a switching transistor and a ring oscillator, where the control terminal of the switching transistor is connected to a control signal terminal, and the second terminal is connected to the wordline signal terminal, with the ring oscillator's power terminal connected to the wordline signal terminal. The ring oscillator, comprising an odd number of inverters, periodically changes resistance to pull down high levels on the wordline signal, reducing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the gate oxide layer is made thinner to enable miniaturization of memory cells, then the integration density is improved, but the leakage current increases due to GIDL phenomenon
Solution Approach 1:
The patent applies periodic action by using a ring oscillator to generate periodic oscillating signals that are applied to the wordline. This periodic voltage variation prevents the wordline from staying continuously at high voltage, thereby reducing the GIDL effect in the N-type transistor while maintaining miniaturization benefits
Solution Approach 2:
The patent introduces a ring oscillator as an intermediary component between the wordline driving circuit and the memory cell array. This intermediary generates oscillating signals that mediate the voltage state of the wordline, preventing direct continuous high voltage application that causes GIDL leakage
2Duration of action of moving object
If the wordline signal is maintained at high level for extended periods, then the read operation is completed, but the leakage current increases causing negative effects on transistor reliability
Solution Approach 1:
The ring oscillator generates periodic oscillating signals that superimpose on the wordline signal. This causes the wordline voltage to periodically vary even during read operations, preventing sustained high voltage conditions that generate GIDL leakage current while still allowing complete read operations
Solution Approach 2:
The patent changes the voltage parameter of the wordline from a static high level to a dynamically oscillating signal. The ring oscillator modifies the voltage characteristics by adding periodic variations, thereby reducing the average voltage stress on the N-type transistor and minimizing leakage current generation
Data Source
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AI summary
The present disclosure relates to the field of memory technologies. Various embodiments provide a wordline driving circuit. The wordline driving circuit includes a switching transistor and a ring oscillator. A control terminal of the switching transistor is connected to a first control signal terminal, a first terminal of the switching transistor is connected to a drive voltage terminal, and a second terminal of the switching transistor is connected to a wordline signal terminal. A power terminal of the ring oscillator is connected to the wordline signal terminal, and a ground terminal of the ring oscillator is a ground terminal of the wordline driving circuit. The wordline driving circuit in accordance with the present disclosure can enhance device reliability and service life for the wordline driving circuit.