Back-Gate Transistor Circuit for Threshold Voltage Stabilization
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Solution Overview
Problem
Semiconductor devices with metal oxide transistors face challenges in controlling threshold voltage and are prone to performance changes due to temperature variations, leading to reliability and power consumption issues.
Innovation Solution
A semiconductor device incorporating a first transistor with a back gate, a capacitor, and switches to control voltage inputs, utilizing a monitor circuit to adjust gate and back gate voltages to stabilize threshold voltages and reduce temperature-induced performance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal oxide transistor is used, then extremely low off-state current is achieved, but threshold voltage control becomes difficult
Solution Approach 1:
The gate control is segmented into two independent gates: a first gate electrode for controlling the threshold voltage and a second gate electrode for adjusting the threshold voltage. This segmentation allows independent control of threshold voltage without affecting the low off-state current characteristic of the metal oxide transistor channel.
2Ease of operation
If conventional Si transistor is used, then threshold voltage can be easily controlled by impurity introduction, but off-state current is higher compared to metal oxide transistors
Solution Approach 1:
The patent replaces the chemical impurity introduction method (used in Si transistors) with an electrical control method using dual gates. The threshold voltage is controlled by applying appropriate voltages to the first and second gate electrodes, substituting mechanical/chemical processes with electrical fields to achieve threshold voltage control in metal oxide transistors.
3Ease of operation
If the threshold voltage of an OS transistor is controlled by providing a first gate electrode and a second gate electrode, then threshold voltage control is achieved, but device complexity increases
Solution Approach 1:
The first gate electrode serves multiple functions: it controls the threshold voltage during normal operation and also serves as a control electrode for adjusting the threshold voltage when needed. The second gate electrode provides additional threshold voltage adjustment capability. This multi-functionality reduces the need for separate adjustment circuits, thereby managing device complexity.
4Stability of the object's composition
If voltage adjustment circuits are added to stabilize threshold voltage, then temperature-induced performance changes are reduced, but device complexity and power consumption increase
Solution Approach 1:
The first and second gate electrodes enable the transistor to self-adjust its threshold voltage in response to temperature changes. By applying appropriate voltages to these gates, the transistor can compensate for temperature-induced threshold voltage shifts without requiring external monitoring circuits or complex adjustment mechanisms, achieving self-stabilization.
Data Source
AI summary
A semiconductor device capable of obtaining the threshold voltage of a transistor is provided. The semiconductor device includes a first transistor, a first capacitor, a first output terminal, a first switch, and a second switch. A gate and a source of the first transistor are electrically connected to each other. A first terminal of the first capacitor is electrically connected to the source. A second terminal and the first output terminal of the first capacitor are electrically connected to a back gate of the first transistor. The first switch controls input of a first voltage to the back gate. A second voltage is input to a drain of the first transistor. The second switch controls input of a third voltage to the source.