HEMT Gate Region Layout Using Crystallographic Alignment
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Solution Overview
Problem
Existing high-electron mobility transistors (HEMTs) face challenges in improving steady-state conduction characteristics without compromising other critical parameters such as threshold voltage, gate current, and linear region characteristics.
Innovation Solution
The design incorporates a semiconductor body with a barrier region and a channel region of type III-V semiconductor material, forming a heterojunction that creates a two-dimensional charge carrier gas channel. This design includes first and second electrodes in low-ohmic contact with the channel and a gate structure with a doped type III-V semiconductor material region, where the side faces of the doped region are aligned along crystallographically equivalent planes to optimize the transistor's geometry and reduce leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the geometry of the doped region is optimized to improve steady-state conduction characteristics, then conduction performance is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by optimizing the geometric parameters of the doped region, specifically setting the lateral boundaries to extend along crystallographically equivalent planes at specific angles (e.g., 60 degrees in wurtzite structure). This geometric parameter optimization improves steady-state conduction characteristics by reducing leakage currents and enhancing carrier transport, while the changes are confined to the doped region geometry rather than the entire device structure.
Solution Approach 2:
The patent implements local quality by applying the crystallographic alignment requirement specifically to the doped region's lateral boundaries, while other parts of the device maintain conventional structures. The doped region is locally optimized with sides extending along crystallographically equivalent planes, creating heterogeneous properties within the device - the aligned doped region provides improved conduction where needed, while other regions maintain simplicity.
2Reliability
If crystallographic alignment is implemented in the doped region to reduce leakage, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise angular parameters for the doped region geometry, requiring lateral boundaries to extend along crystallographically equivalent planes at specific angles (e.g., 60 degrees for wurtzite structure). This parameter specification provides clear manufacturing targets that can be achieved through controlled epitaxial growth and lithography processes, balancing the need for precision with manufacturability.
Solution Approach 2:
The patent employs preliminary action by pre-defining the crystallographic orientation requirements during the design and fabrication planning stages. The doped region is formed with predetermined geometric parameters that align with the substrate's crystallographic axes, allowing subsequent processing steps to proceed with standard precision requirements rather than requiring post-fabrication alignment adjustments.
3Reliability
If the doped region geometry is optimized with crystallographic alignment, then conduction characteristics are improved, but threshold voltage control becomes more difficult
Solution Approach 1:
The patent applies local quality by optimizing only the lateral geometry of the doped region while maintaining independent control over the vertical doping profile and gate structure. The crystallographic alignment is applied locally to the doped region's lateral boundaries, while the doping concentration, depth, and gate electrode parameters can be independently adjusted to control threshold voltage, preserving design flexibility in critical parameters.
Solution Approach 2:
The patent segments the device optimization into independent functional regions: the doped region geometry is optimized for conduction characteristics with crystallographic alignment, while the gate structure and doping profile remain separately controllable for threshold voltage adjustment. This segmentation allows each parameter set to be optimized independently without compromising the other.
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 configuration enhances the steady-state conduction characteristics of the HEMT while maintaining optimal threshold voltage, gate current, and linear region characteristics, thereby improving the overall performance of the device.
Implementation Method 1
a channel region of type III-V semiconductor material that forms a heterojunction with the barrier region, thereby forming a two-dimensional charge carrier gas channel within the channel region
Implementation Method 2
An HEMT includes a two-dimensional charge carrier gas that is created by a heterojunction between two layers of type III-V semiconductor material having different band gaps
Implementation Method 3
a gate structure comprising a gate electrode and a first region of doped type III-V semiconductor material in between the gate electrode and the two-dimensional charge carrier gas channel
Data Source
AI summary
A high-electron mobility transistor includes a semiconductor body including a barrier region, a channel region, and a two-dimensional charge carrier gas channel, first and second electrodes that are each in electrical contact with the two-dimensional charge carrier gas channel, and a gate structure laterally in between the first and second electrodes, wherein the gate structure comprises a gate electrode and a first region of doped type III-V semiconductor material in between the gate electrode and the two-dimensional charge carrier gas channel, wherein the first region of doped type III-V semiconductor material comprises a plurality of side faces that define a plan view geometry of the first region, and wherein in the plan view geometry of the first region at least two lateral boundaries of the first region that intersect one another extend along crystallographically equivalent planes of the doped type III-V semiconductor material.