Double-Gate Semiconductor Device for High Breakdown Voltage
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Solution Overview
Problem
Conventional CMOS devices for RF power applications face a tradeoff between improved RF performance and higher breakdown voltage, with reduced breakdown voltage limiting voltage swing and usefulness in power applications.
Innovation Solution
A high-breakdown voltage double-gate semiconductor device is developed, comprising a metal-oxide-semiconductor gate and a junction gate, where the effective resistance is controlled by coupling circuitry to manage current flow between the drain and source, enhancing breakdown voltage and RF capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gate geometries are reduced to improve RF performance, then RF performance is improved, but breakdown voltage is reduced
Solution Approach 1:
The device is divided into two separate gates: a first gate (MOS gate) for controlling RF performance and a second gate (junction gate) for controlling breakdown voltage. This segmentation allows independent optimization of each function, resolving the contradiction between RF performance and breakdown voltage by assigning each gate a specific role.
Solution Approach 2:
The device allows dynamic control of the channel conductivity through the first gate and dynamic control of the pinchoff voltage through the second gate. This dynamic control capability enables the device to adaptively optimize both RF performance and breakdown voltage depending on operating conditions.
2Power
If transistor width is increased to achieve greater current drive, then current drive is improved, but capacitive load increases
Solution Approach 1:
The invention changes the electrical parameters of the device by introducing a second gate that independently controls pinchoff voltage. This allows current drive to be optimized through parameter control rather than simply increasing device width, thereby reducing the associated capacitive load while maintaining or improving current drive capability.
3Strength
If drift region doping concentration is limited to achieve higher breakdown voltage, then breakdown voltage is improved, but on-state resistance increases
Solution Approach 1:
The device structure is segmented into a drift region for breakdown voltage control and a channel region controlled by the second gate for resistance management. This segmentation allows the drift region to be optimized for high breakdown voltage with limited doping, while the channel region under the second gate provides a low-resistance path during conduction, reducing on-state resistance losses.
Solution Approach 2:
The second gate acts as an intermediary element that provides a controlled conduction path through the drift region. By applying appropriate voltages to the second gate, a conductive channel is formed that mediates between the high-impedance drift region (optimized for breakdown voltage) and the external circuit, thereby reducing on-state resistance without compromising breakdown voltage.
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
The double-gate semiconductor device achieves improved RF performance and higher power handling capabilities compared to conventional CMOS devices, with a high breakdown voltage enabling larger voltage excursions suitable for power applications.
Implementation Method 1
a first gate formed on an oxide layer disposed on the substrate, a well region having a second conductivity type and formed substantially in the substrate, and a drain formed substantially in the well region... a current flowing in high-breakdown voltage double-gate semiconductor device is responsive to a voltage applied to the second gate
Data Source
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AI summary
A double-gate semiconductor device provides a high breakdown voltage allowing for a large excursion of the output voltage that is useful for power applications. The double-gate semiconductor device may be considered a double-gate device including a MOS gate and a junction gate, in which the bias of the junction gate may be a function of the gate voltage of the MOS gate. The breakdown voltage of the double-gate semiconductor device is the sum of the breakdown voltages of the MOS gate and the junction gate. Because an individual junction gate has an intrinsically high breakdown voltage, the breakdown voltage of the double-gate semiconductor device is greater than the breakdown voltage of an individual MOS gate. The double-gate semiconductor device provides improved RF capability in addition to operability at higher power levels as compared to conventional transistor devices.