HEMT Field Plate Layout for Lower RC Effect in Fast Switching
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Solution Overview
Problem
High-electron-mobility transistors (HEMTs), particularly GaN power HEMTs, face challenges in reducing gate to drain spacing due to the distributed RC effect caused by field plates, especially under high frequency and high dvdt switching environments, which affects their performance.
Innovation Solution
A field plate is electrically isolated from the gate structure and abuts the source and drain contacts, reducing field crowding and improving field distribution, while being separated from the gate metal contact by sidewall spacers, thereby enhancing device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If field plates are used to reduce gate to drain spacing, then device optimization is improved, but distributed RC effect increases under high frequency high dv/dt switching environments
Solution Approach 1:
The field plate is segmented into multiple sections with different grounding configurations. The first field plate section is grounded while the second field plate section is electrically isolated from the gate structure, creating distinct functional zones that reduce the distributed RC effect while maintaining device optimization benefits
Solution Approach 2:
An insulating layer is introduced as an intermediary between the field plate and the gate structure, electrically isolating the field plate from the gate while allowing the field plate to maintain its position and function in reducing gate to drain spacing
2Object-generated harmful factors
If field plate is electrically isolated from gate structure, then distributed RC effect is reduced, but field distribution uniformity decreases
Solution Approach 1:
Different sections of the field plate have different electrical characteristics - the first section is grounded to provide stable field distribution near the gate, while the second section is electrically isolated to reduce RC effects in the drain region, creating locally optimized field conditions
Solution Approach 2:
The field plate structure extends in the vertical dimension with multiple stacked sections, allowing independent electrical control of each section to simultaneously achieve field uniformity near the gate and RC effect reduction in the drain region
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to a high-electron-mobility transistor (HEMT) and methods of manufacture. The structure includes: a gate structure; a source contact and a drain contact adjacent to the gate structure; and a field plate electrically isolated from the gate structure and abutting the source contact and the drain contact.