Serial MOS Transistor Sense Amplifier Layout and Voltage Compensation
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Solution Overview
Problem
Semiconductor devices, particularly DRAMs, face challenges in reducing size and power consumption while maintaining performance, as lowering operating voltage in sense amplifiers leads to increased leakage current and power consumption, and existing solutions like presense amplifiers increase circuit area and complexity.
Innovation Solution
The use of serially connected MOS transistors with a connection device that forms a connection node between them, allowing for efficient layout at a small pitch and reducing the overall layout area, and the implementation of a presense amplifier structure that compensates for voltage reduction effects in sense amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the operating voltage of sense amplifiers is decreased to reduce power consumption, then power consumption is reduced, but operation speed decreases and sufficient amplification cannot be performed
Solution Approach 1:
The patent changes the threshold voltage parameter of the MOS transistors in the sense amplifier to a lower value, enabling the amplifier to maintain sufficient amplification capability and operation speed even when the operating voltage is reduced. This parameter change allows the sense amplifier to operate effectively at lower voltages without sacrificing performance.
2Reliability
If the threshold voltage of transistors in sense amplifiers is lowered to maintain performance at low operating voltage, then amplification capability is maintained, but leakage current increases and power consumption increases
Solution Approach 1:
The patent introduces dynamic control of the transistor threshold voltage through a control voltage signal. The threshold voltage is adjusted dynamically based on operating conditions, allowing the sense amplifier to maintain low threshold voltage (for good amplification) only when needed during active operation, while reducing leakage current during standby or non-active periods.
Solution Approach 2:
The control voltage applied to adjust the transistor threshold voltage is applied periodically or in pulses corresponding to the operation cycles of the sense amplifier. The threshold voltage is lowered only during the periods when amplification is required, and restored to normal levels during other periods, thereby reducing overall leakage current while maintaining amplification capability when needed.
3Reliability
If presense amplifiers are added to compensate for voltage reduction effects, then amplification performance is improved, but circuit area increases and device complexity increases
Solution Approach 1:
The patent merges the voltage compensation function into the existing sense amplifier structure by adding control voltage generation circuits and threshold voltage adjustment mechanisms within the same amplifier block. This integration allows the sense amplifier to compensate for voltage reduction effects internally without requiring separate presense amplifier circuits, thereby avoiding the increase in circuit area and device complexity.
Solution Approach 2:
The sense amplifier is designed with multi-functionality, where the same amplifier structure performs both the primary amplification function and the voltage compensation function. By making the sense amplifier universal in its capabilities, the patent eliminates the need for additional dedicated presense amplifier circuits, thus reducing circuit area and complexity while maintaining amplification performance.
4Reliability
If presense amplifiers are added to compensate for voltage reduction effects, then amplification performance is improved, but the number of structural elements and control signals increases
Solution Approach 1:
The patent combines the voltage compensation functionality into the existing sense amplifier structure by integrating control voltage generation circuits and threshold voltage adjustment mechanisms within the same amplifier block. This merging approach allows the sense amplifier to compensate for voltage reduction effects internally without requiring separate presense amplifier circuits, thereby avoiding the increase in the number of structural elements and control signals.
Data Source
AI summary
A semiconductor device includes a plurality of signal lines which are arranged at a predetermined pitch; first and second MOS transistors which are connected to the signal lines, and also serially connected to each other; and a connection device which functions as a connection node between the serially-connected first and second MOS transistors, and connects a source area of one of the first and second MOS transistors to a drain area of the other of the first and second MOS transistors via contact holes, which are formed through an insulating layer, and a conduction layer connected to the contact holes.