Mobility-Modulated Transistors for Beyond-Transition-Frequency Operation
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Solution Overview
Problem
Existing semiconductor devices are limited by their transition frequency, restricting their ability to operate at higher frequencies due to dependencies on transit time and gate parasitic capacitances, which hinders their performance in applications requiring faster switching rates or higher frequency operations.
Innovation Solution
The introduction of a mobility modulator in semiconductor devices that applies electric, magnetic, or electromagnetic fields across a drift region between device terminals, allowing for the modulation of charge-carrier mobility as a function of longitudinal position, thereby decoupling operating frequency from transit time and enabling operation above the transition frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional semiconductor devices operate at higher frequencies, then frequency performance is improved, but transit time and gate parasitic capacitances limit the maximum operating frequency
Solution Approach 1:
The patent applies dynamics by making the charge carrier mobility variable through time-dependent modulation. A mobility modulator dynamically adjusts the mobility of charge carriers in the drift region using modulation signals, allowing the device to operate at frequencies above the traditional transition frequency where conventional static devices fail. This dynamic control enables the device to adapt its electrical characteristics in real-time to achieve higher frequency operation.
Solution Approach 2:
The patent changes the fundamental parameter of charge carrier mobility from a fixed value to a modulated variable. By introducing a mobility modulator that applies electric, magnetic, or electromagnetic fields to the drift region, the mobility of charge carriers becomes a controllable parameter that can be adjusted through modulation signals, thereby extending the device's frequency response beyond traditional limits.
2Speed
If faster switching rates are achieved through conventional means, then switching speed is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the frequency-limiting constraints from the conventional device structure by introducing a separate mobility modulator component. This modulator independently controls charge carrier mobility without requiring fundamental changes to the core transistor architecture, thereby achieving fast switching rates while maintaining relatively simple device fabrication processes compatible with existing semiconductor manufacturing.
3Speed
If operation beyond transition frequency is enabled, then frequency range is extended, but dependencies on transit time and parasitic capacitance become more significant
Solution Approach 1:
The patent converts the harmful effects of transit time and parasitic capacitance into beneficial effects by using mobility modulation. The mobility modulator applies timed electric, magnetic, or electromagnetic fields that counteract and compensate for the phase delays and signal degradation caused by transit time and parasitic capacitance, transforming these previously limiting factors into controllable parameters that can be optimized for high-frequency operation.
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
This approach allows semiconductor devices to operate at frequencies significantly above their transition frequency, enabling faster switching rates and simpler, lower-cost process nodes, with applications in oscillators, amplifiers, mixers, and multipliers, and other electronic circuits.
Implementation Method 1
The mobility modulator is configured to modulate the mobility of the charge-carriers by selectively applying one or both of an electric field and a magnetic field to at least part of the drift region
Implementation Method 2
The mobility modulator is configured to modulate the mobility of the charge-carriers by selectively applying one or both of an electric field and a magnetic field to at least part of the drift region
Implementation Method 3
The mobility modulator applies electric, magnetic, or electromagnetic fields across a drift region between device terminals
Implementation Method 4
the mobility modulator configured to modulate the mobility of the charge-carriers by causing a scattering of some charge-carriers that impinge on the interface region
Data Source
AI summary
A network device includes one or more circuit components. The one or more circuit components include a semiconductor substrate, a first device terminal and a second device terminal, a drift region, and a mobility modulator. Both device terminals are coupled to the semiconductor substrate, the second device terminal being spatially separated from the first device terminal. The drift region is disposed on the semiconductor substrate between the first device terminal and the second device terminal, the drift region being configured to allow a flow of charge-carriers between the first device terminal and the second device terminal. The mobility modulator is coupled to the drift region, the mobility modulator being configured to selectively apply a field across the drift region responsive to one or more modulation signals, so as to modulate a mobility of charge-carriers as a function of longitudinal position along the drift region.