Enhancement-Mode III-V HEMT Using All-Solid-State Battery
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Solution Overview
Problem
Existing methods for obtaining enhancement-mode III-V HEMTs, such as trench gate technology, pn junction injection, and F ion implantation, face challenges like inaccurate etching, high material costs, and reliability issues, making it difficult to achieve the necessary depletion of 2DEG for practical applications.
Innovation Solution
An enhancement-mode III-V HEMT is developed using an all-solid-state battery structure, where a second semiconductor layer and a first semiconductor layer form a heterostructure, with an all-solid-state battery and diode pair generating a negative potential between the gate and source electrodes to deplete electrons in the channel, eliminating the need for etching and reducing material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trench gate technology is used to etch AlGaN below gates, then 2DEG depletion in channels is achieved, but etching depth accuracy is poor and channel damage occurs
Solution Approach 1:
The invention extracts and removes the problematic etching step entirely by replacing trench gate technology with an all-solid-state battery structure. The battery's natural potential difference directly depletes 2DEG without requiring physical etching of the AlGaN layer, thus eliminating both etching depth inaccuracy and channel damage while achieving reliable enhancement-mode operation.
Solution Approach 2:
The mechanical/chemical etching process is replaced with an electrochemical system (all-solid-state battery). The battery generates an electric field through its internal chemistry that depletes 2DEG electrons, substituting the mechanical removal approach with a field-based control mechanism that is more precise and less damaging.
2Reliability
If pn junctions are injected below gates, then 2DEG depletion is achieved, but material growth cost increases significantly
Solution Approach 1:
The invention uses inexpensive all-solid-state battery materials (lithium phosphate ceramic, lithium cobalt oxide, nickel, titanium) to replace expensive P-type materials required for pn junction injection. The battery structure achieves the same 2DEG depletion effect using cost-effective materials that can be deposited through standard sputtering processes.
Solution Approach 2:
The invention changes the material parameter from expensive P-type semiconductors to affordable battery electrode materials. By altering the material composition to lithium-based ceramics and metal oxides, the solution maintains electrical functionality for 2DEG depletion while dramatically reducing material costs.
3Reliability
If F ion implantation is used to deplete 2DEG, then enhancement-mode operation is achieved, but control accuracy is poor and reliability problems arise
Solution Approach 1:
The all-solid-state battery is a self-contained device that automatically maintains the required negative potential on the gate through its internal electrochemical reactions. The battery self-regulates the depletion of 2DEG without requiring external control mechanisms, eliminating the precision control problems associated with ion implantation dosing and timing.
Solution Approach 2:
The battery is pre-assembled and pre-charged to establish the required negative potential before device operation. This preliminary preparation ensures consistent and accurate 2DEG depletion from the start, avoiding the real-time control inaccuracies inherent in ion implantation processes.
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 ensures high electron mobility and performance by avoiding etching-related issues, ensuring high reliability and compatibility with micro-nano machining processes, while allowing for adjustable threshold voltage through the number of battery units.
Implementation Method 1
an all-solid-state battery is arranged between the source electrode (5) and the gate electrode (12), is composed of at least one group of battery units connected in series or connected in series and parallel, and is used to deplete the 2DEG in a corresponding region of the hetero structure
Implementation Method 2
a negative potential is generated between the gate electrode (12) and source electrode (5) of the all-solid-state battery to deplete electrons in channels close to the gate electrode (12)
Implementation Method 3
natural GaN-based HEMTs generate high spontaneous polarization and piezoelectric polarization in AlGaN/GaN-based heterojunctions due to the symmetry of crystal structures as well as high-concentration 2DEG (2 dimensional electron gas) at interfaces of the heterojunctions
Data Source
AI summary
An enhancement-mode III-V HEMT based on an all-solid-state battery is provided. In which, a second semiconductor layer and a first semiconductor layer are sequentially formed on a substrate, and a heterostructure is formed between the second semiconductor layer and the first semiconductor layer; a source electrode is electrically connected to a drain electrode through a 2DEG generated in the heterostructure; a gate electrode is used to control on-off of the 2DEG in the heterostructure; and an all-solid-state battery is arranged between the source electrode and the gate electrode, is composed of at least one group of battery units connected in series or connected in series and parallel, and is used to deplete the 2DEG in a corresponding region of the heterostructure.