HEMT Structure With Mesa Isolation and Doped Layer Integration
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Solution Overview
Problem
Existing GaN-based high electron mobility transistors (HEMTs) face challenges in achieving optimal electrical and mechanical performance due to limitations in doped layer integration and device isolation.
Innovation Solution
The proposed HEMT structure includes a first doped layer in a substrate, mesa isolation, a gate electrode, source and drain electrodes, a passivation layer, and metal lines connecting the electrodes to the doped layer, enhancing device isolation and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If doped layer integration is improved to enhance electrical performance, then device isolation becomes more difficult to achieve
Solution Approach 1:
The patent divides the device structure into distinct segments: the doped layer is confined to specific regions within the substrate, and mesa isolations are introduced to create physical separation between adjacent devices. This segmentation allows the doped layer to provide electrical performance in active regions while mesa isolations provide device isolation in non-active regions, resolving the contradiction between improving electrical performance and achieving device isolation.
Solution Approach 2:
The patent applies local quality by having the doped layer present only in specific locations (within the substrate beneath the active device regions) rather than uniformly throughout. The mesa isolations are strategically positioned to provide isolation where needed while leaving the doped layer intact in regions where electrical performance is required. This localized approach allows simultaneous optimization of both electrical performance and device isolation.
2Reliability
If device isolation is enhanced using mesa isolation structures, then doped layer integration becomes more challenging
Solution Approach 1:
The patent implements preliminary action by forming the doped layer in the substrate before creating the mesa isolation structures. This sequence allows the doped layer to be integrated into the substrate first, establishing the electrical performance foundation, and then the mesa isolations are formed to provide device isolation without disrupting the already-integrated doped layer. This preliminary integration simplifies the overall process compared to attempting to integrate the doped layer after mesa structures are in place.
Data Source
AI summary
A high electron mobility transistor (HEMT) includes a first doped layer disposed in a substrate, a mesa isolation disposed on the substrate, a gate electrode disposed on the mesa isolation, a source electrode and a drain electrode disposed adjacent to two sides of the gate electrode, a passivation layer disposed on the mesa isolation and around the source electrode and the drain electrode, a first metal line connecting the source electrode and the first doped layer, and a second metal line connecting the drain electrode and the first doped layer.