Gate-Controlled Energy Filtering in Semiconductor Devices
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Solution Overview
Problem
Current semiconductor devices face limitations in reducing leakage currents, which restrict further downscaling of chip sizes due to the subthreshold slope, leading to a trade-off between power consumption and performance, and existing device architectures have room for improvement in design.
Innovation Solution
The introduction of interference structures within semiconductor devices that induce local mini-band structures, allowing for voltage-controlled alignment or misalignment with other band structures to manage current flow, thereby reducing leakage currents and steepening the subthreshold slope without requiring abrupt transistor turn-off or steep doping profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the field-effect transistor's threshold voltage is scaled down to reduce dynamic power, then power consumption is reduced, but leakage current increases exponentially
Solution Approach 1:
The channel is segmented into multiple quantum wells separated by barriers, creating a multi-level energy structure. This segmentation allows independent control of electron transport at different energy levels, enabling steep subthreshold slope without exponential leakage increase when scaling threshold voltage.
Solution Approach 2:
The patent employs dynamically controllable quantum well depths and barrier heights through gate voltages. By dynamically adjusting the energy levels of quantum wells and barriers, the device achieves abrupt current switching while maintaining low leakage, resolving the trade-off between power reduction and leakage control.
2Ease of manufacture
If conventional MOSFET structures are used, then manufacturing is straightforward, but the subthreshold slope is limited to at least 60 mV per decade of current
Solution Approach 1:
The patent changes the fundamental parameter of electron transport from classical diffusion to quantum mechanical tunneling and resonant transport. By engineering specific quantum well depths, barrier widths, and alignment conditions, the device achieves sub-60mV/decade subthreshold slope while remaining manufacturable through standard semiconductor processing techniques.
3Productivity
If quantum mechanical features are employed to overcome subthreshold slope limits, then switching performance improves, but device design complexity increases
Solution Approach 1:
The patent applies quantum mechanical structures locally within specific channel regions rather than throughout the entire device. The quantum wells and barriers are positioned at critical locations to control carrier injection and transport, achieving enhanced switching performance while minimizing overall device complexity and maintaining compatibility with conventional manufacturing.
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 for a higher on-current while maintaining a steeper subthreshold slope, reducing susceptibility to surface scattering, and eliminating the need for band-to-band tunnelling, resulting in improved power-performance trade-offs and device performance.
Implementation Method 1
The first interference structure is formed to induce a first local mini-band structure
Implementation Method 2
the first local mini-band structure is aligned with another band structure in the semiconductor device to turn the semiconductor device on and misaligned to turn it off
Implementation Method 3
the mini-bandgaps filter out the electrons that would otherwise form the subthreshold current
Implementation Method 4
eliminating the need for band-to-band tunnelling
Data Source
AI summary
The present disclosure relates to semiconductor devices with gate-controlled energy filtering. One example embodiment includes a semiconductor device. The semiconductor device includes a first electrode, a second electrode, and a channel therebetween. The semiconductor device also includes a first interference structure located in the channel. Further, the semiconductor device includes a first gate for controlling a voltage over the first interference structure. The first interference structure is formed to induce a local mini-band structure that can be shifted by the voltage controlled by the first gate, such that the first local mini-band structure is: (1) aligned with a band structure in the semiconductor device to turn the semiconductor device on; and (2) misaligned with the band structure in the semiconductor device to turn the semiconductor device off.