HEMT Dielectric Stack With Different Etch Rates for Seam Control
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Solution Overview
Problem
Ordinary semiconductor structures used in high electron mobility transistors (HEMTs) face reliability issues due to damage from plasma or ion processes and seam-related problems in dielectric layers, leading to unreliable performance.
Innovation Solution
A semiconductor structure is developed with a stack of multilayer dielectric layers having different etching rates, which are designed to resist wet etching solutions and prevent damage to underlying features, thereby enhancing the reliability of the semiconductor structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an ordinary dielectric layer is used in HEMT, then the device can be manufactured with simple structure, but damage occurs from plasma/ion processes and seam defects reduce reliability
Solution Approach 1:
The patent divides a single dielectric layer into multiple dielectric layers with different etching rates. This segmentation allows the top layer to protect against plasma/ion damage while the bottom layer provides structural support, thereby improving device reliability without excessive complexity increase.
Solution Approach 2:
The patent uses composite dielectric layer structure where layers with different etching rates are combined. The first dielectric layer has a first etching rate and the second dielectric layer has a second etching rate, creating a composite structure that simultaneously provides damage resistance and structural integrity.
2Reliability
If a single dielectric layer is used, then manufacturing is simple, but seam defects and plasma damage occur reducing performance
Solution Approach 1:
The dielectric layer is segmented into multiple layers with different etching characteristics. The first dielectric layer is formed with a first etching rate and the second dielectric layer with a second etching rate, allowing selective protection during manufacturing processes while maintaining fabricability.
Solution Approach 2:
Different regions of the dielectric structure have different etching rates tailored to specific functional requirements. The top layer has properties optimized for plasma resistance while the bottom layer has properties optimized for structural support, achieving local quality optimization.
3Object-affected harmful factors
If multilayer dielectric structure is implemented, then protection against etching solutions and thermal spiking is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs composite dielectric layers where the first dielectric layer with a first etching rate provides protection against etching solutions and thermal spiking, while the second dielectric layer with a second etching rate provides structural support. This composite approach addresses multiple harmful factors simultaneously.
Solution Approach 2:
The first dielectric layer acts as a protective cushion against plasma/ion damage, etching solution penetration, and thermal spiking effects before these harmful factors can reach the underlying transistor structures. This prior cushioning prevents damage before it occurs.
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
The use of multilayer dielectric layers with varying etching rates reduces the formation of seams and defects, protects metal components from etching solutions, and prevents the spiking effect during thermal processes, resulting in improved reliability and performance of HEMTs.
Implementation Method 1
The stack of dielectric layers includes layers having different etching rates
Implementation Method 2
prevents the spiking effect during thermal processes
Data Source
AI summary
A semiconductor structure is provided. The semiconductor structure includes a substrate, a channel layer, a barrier layer, a compound semiconductor layer, a gate electrode, and a stack of dielectric layers. The channel layer is disposed on the substrate. The barrier layer is disposed on the channel layer. The compound semiconductor layer is disposed on the barrier layer. The gate electrode is disposed on the compound semiconductor layer. The stack of dielectric layers is disposed on the gate electrode. The stack of dielectric layers includes layers having different etching rates.