P-Type Gate HEMT Structure for Lower Leakage and Stronger Control
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Solution Overview
Problem
Conventional high electron mobility transistors (HEMTs) face issues with leakage current and gate control capability, which are not adequately addressed by existing technologies.
Innovation Solution
The HEMT device design includes a gate structure with a P-type group III-V semiconductor layer that has a larger upper portion than lower portion, increasing the contact area with the metal layer, thereby enhancing the Schottky diode current and two-dimensional electron gas density, improving gate control capability and reducing drain-induced barrier lowering and subthreshold swing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional HEMT structure is used, then the device can operate as a field effect transistor, but the leakage current is high and gate control capability is insufficient
Solution Approach 1:
The gate structure is segmented into multiple functional layers: a P-type group III-V semiconductor layer and a metal layer disposed thereon. This segmentation allows the P-type layer to provide hole injection for improved gate control while the metal layer forms a Schottky contact for effective leakage current suppression, resolving the contradiction between gate control capability and leakage current reduction
Solution Approach 2:
The gate structure employs a composite material system combining P-type group III-V semiconductor material with metal materials. This composite structure enables simultaneous achievement of high gate control capability through hole injection from the P-type layer and low leakage current through the Schottky barrier formed at the metal-semiconductor interface
2Quantity of substance
If the contact area between metal layer and P-type semiconductor layer is increased, then the Schottky diode current increases and 2DEG density improves, but the device structure becomes more complex
Solution Approach 1:
The P-type group III-V semiconductor layer is designed with a T-shaped cross-section where the upper portion extends laterally beyond the lower portion. This dimensional extension in the lateral direction increases the contact area between the P-type layer and metal layer without adding vertical layers, thereby increasing Schottky diode current and 2DEG density while maintaining relatively simple device structure
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 design effectively increases the Schottky diode current, enhances two-dimensional electron gas density, and improves gate control capability, while reducing leakage current and improving the subthreshold swing of the HEMT device.
Implementation Method 1
increases the Schottky diode current by enlarging the contact area between the metal layer and the P-type group III-V semiconductor layer
Implementation Method 2
a large number of the electron holes (or positive charges) in the P-type group III-V semiconductor layer is injected into the two-dimensional hole gas layer, thereby increasing the two-dimensional electron gas density
Data Source
AI summary
A high electron mobility transistor (HEMT) device and a method of forming the HEMT device are provided. The HEMT device includes a substrate, a channel layer, a barrier layer, and a gate structure. The substrate has at least one active region. The channel layer is disposed on the at least one active region. The barrier layer is disposed on the channel layer. The gate structure is disposed on the barrier layer. The gate structure includes a metal layer and a P-type group III-V semiconductor layer vertically disposed between the metal layer and the barrier layer. The P-type group III-V semiconductor layer includes a lower portion and an upper portion on the lower portion, and the upper portion has a top area greater than a top area of the lower portion.