Magnetic Field Controlled Transistor Circuit for Sub-0.5V Operation
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Solution Overview
Problem
The scaling of CMOS technology and low-power circuits is limited by the inability to reduce power consumption and power density below 0.5 V due to the 60 mV/decade limit in Field Effect Transistors, and high-frequency amplifiers have reached a performance plateau with III-V HEMTs.
Innovation Solution
A magnetic field controlled transistor circuit using a magneto-resistive channel and a control layer with an insulating layer in between, where a control current induces a magnetic field to control the resistivity of the channel, allowing for reduced supply voltage and enhanced performance in high-frequency amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Field Effect Transistors are used for scaling, then device density increases, but supply voltage cannot be scaled below 0.5 V due to the 60 mV/decade limit
Solution Approach 1:
The patent replaces the conventional electric field control mechanism in FETs with a magnetic field control mechanism. The control layer generates a magnetic field that penetrates the insulating layer to modulate the channel conductivity, substituting the traditional voltage-based electric field control with magnetic field-based control. This allows the device to operate at lower supply voltages while maintaining high device density.
2Device complexity
If conventional FET control mechanism is used, then device structure is simple, but supply voltage scaling is limited to above 0.5 V
Solution Approach 1:
The patent introduces an insulating layer as an intermediary between the control layer and the channel. This insulating layer allows magnetic field penetration while providing electrical isolation, enabling the control layer to modulate channel conductivity without direct electrical contact. This intermediary structure enables lower supply voltage operation while adding controlled complexity to the transistor architecture.
3Productivity
If III-V HEMTs are used for high-frequency amplifiers, then transconductance performance is maximized, but performance has reached a plateau around 3 mS/μm
Solution Approach 1:
The patent changes the fundamental control parameter from electric field (voltage) to magnetic field. The control layer's magnetization state, controlled by applied magnetic fields or currents, modulates the channel conductivity. This parameter change enables new performance characteristics in high-frequency amplifiers, potentially exceeding the transconductance limits of conventional III-V HEMTs and providing continued performance improvement potential.
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
Enables operation with supply voltages below 0.4 V and achieves high current gain with low capacitance, supporting frequencies over 1 THz and efficient power management.
Implementation Method 1
driving a control current between the third and the fourth electrode through the control layer, thereby applying a magnetic field on the channel
Implementation Method 2
a channel current IDS may flow between the first electrode (11) and the second electrode (12) if a drain-source voltage VDS is applied between the first electrode (11) and the second electrode (12). The magnetic field controlled transistor circuit (100) further comprises a control layer (20) which may also be denoted as control channel (20). The control layer (20) comprises an electrically conductive material.
Implementation Method 3
an insulating layer (30) comprising an electrically insulating material (31). The insulating layer (30) is arranged between the channel (10) and the control layer (20) and electrically insulates the channel (10), the first electrode (11) and the second electrode (12) from the control layer (20)
Data Source
AI summary
A magnetic field controlled transistor circuit includes a first electrode, a second electrode, and a channel including a magneto-resistive material. The channel is arranged between the first and second electrodes and electrically coupled to the first and second electrodes. The transistor circuit further includes a third electrode, a fourth electrode, and a control layer including an electrically conductive material. The control layer is arranged between the third and fourth electrodes and electrically coupled to the third and fourth electrodes. In addition, an insulating layer including an insulating material is provided. The insulating layer is arranged between the channel and the control layer and configured to electrically insulate the channel from the control layer. A related method for operating a transistor circuit and a corresponding design structure are also provided.