HEMT Gate Structure With Electric-Field Relaxation for Leakage Control
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving improved electrical characteristics and high process efficiency, particularly in the design and fabrication of high-electron-mobility transistors (HEMTs) with heterojunction structures, where the existing configurations often lead to leakage currents and uneven electric field distribution.
Innovation Solution
The semiconductor device design includes a channel layer, a channel supply layer, a channel separation pattern, a gate electrode pattern, and an electric-field relaxation pattern, where the gate electrode pattern and electric-field relaxation pattern form a single structure with varying sizes, and passivation films are used to optimize the interface and reduce leakage currents. The method involves forming a conductive material pattern that includes a gate electrode and electric-field relaxation pattern simultaneously, improving the device's electrical characteristics and fabrication efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional gate electrode structure is used in HEMT devices, then the fabrication process is simple, but leakage currents occur and electric field distribution becomes uneven
Solution Approach 1:
The gate electrode structure is segmented into multiple functional regions: a main gate electrode pattern and an electric-field relaxation pattern. This segmentation allows the main gate to control the channel while the relaxation pattern specifically addresses electric field concentration at the lateral edges, thereby reducing leakage currents and improving electrical characteristics without requiring complete structural redesign
Solution Approach 2:
The electric-field relaxation pattern acts as an intermediary element between the main gate electrode and the channel separation pattern. It mediates the electric field distribution by providing a transition zone that prevents field concentration at the gate edges, thus improving reliability without significantly complicating the overall device structure
2Reliability
If separate formation processes are used for gate electrode and electric-field relaxation pattern, then each component can be optimized independently, but fabrication time and process complexity increase
Solution Approach 1:
The gate electrode pattern and electric-field relaxation pattern are formed simultaneously in a single fabrication step using a unified conductive material deposition and patterning process. This merging of formation processes maintains the distinct functional structures while significantly reducing fabrication time and process complexity, thereby improving productivity without compromising the electrical characteristics achieved through structural optimization
3Reliability
If the gate electrode pattern size matches the channel separation pattern size, then the fabrication process is simpler, but electric field concentration occurs at the lateral surfaces
Solution Approach 1:
The gate electrode structure employs asymmetric sizing where the electric-field relaxation pattern extends beyond the main gate electrode pattern at the lateral edges. This asymmetric design intentionally creates a size difference that prevents electric field concentration by providing a gradual transition zone, thereby improving electric field distribution while the precision of pattern formation is maintained through standard photolithography and etching processes
Data Source
AI summary
A semiconductor device includes a channel layer including a channel; a channel supply layer on the channel layer; a channel separation pattern on the channel supply layer; a gate electrode pattern on the channel separation pattern; and an electric-field relaxation pattern protruding from a first lateral surface of the gate electrode pattern in a first direction parallel with an upper surface of the channel layer. An interface between the channel layer and the channel supply layer is adjacent to channel. A size of the gate electrode pattern in the first direction is different from a size of the channel separation pattern in the first direction. The gate electrode pattern and the electric-field relaxation pattern form a single structure.