GaN Semiconductor Device Sacrificial Layer for Passivation Protection
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Solution Overview
Problem
Current semiconductor devices with GaN and AlGaN layers face challenges in reproducibility, uniformity, thermal stability, and dynamic behavior due to passivation layer consumption and plasma-induced charge introduction during etching processes, leading to variations in reverse leakage current and device performance.
Innovation Solution
Incorporating a sacrificial layer above the passivation layer to protect it during etching, allowing for selective removal and reducing passivation layer consumption, which improves the uniformity and thickness control of the passivation layer, thereby enhancing the dynamic behavior and reducing reverse leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passivation layer is used in conventional semiconductor devices, then device protection and insulation are provided, but passivation layer consumption during etching processes leads to variations in thickness and reverse leakage current
Solution Approach 1:
A sacrificial layer is introduced as an intermediary between the etching process and the passivation layer. This sacrificial layer absorbs the etching consumption, preventing direct damage to the passivation layer and maintaining its thickness uniformity across the device structure.
Solution Approach 2:
The sacrificial layer is deposited on the passivation layer before the etching process begins. This preliminary action prepares the structure to withstand subsequent etching steps, ensuring the passivation layer remains intact and uniform throughout the manufacturing process.
2Ease of manufacture
If plasma etching processes are used to form contacts, then precise contact formation is achieved, but plasma-induced charge injection degrades device dynamic behavior
Solution Approach 1:
The sacrificial layer serves as a mediator that absorbs plasma-induced charges during the etching process, preventing these charges from being injected into the passivation layer and degrading device performance.
Solution Approach 2:
The sacrificial layer is designed to be consumed or damaged during the plasma etching process. This disposable layer protects the critical passivation layer from plasma damage, accepting the trade-off of needing to replace or remove it afterward.
3Object-generated harmful factors
If the passivation layer thickness is reduced to lower reverse leakage current, then device leakage is improved, but the passivation layer becomes more susceptible to consumption and damage during etching
Solution Approach 1:
The sacrificial layer provides beforehand cushioning protection to the thin passivation layer. This cushioning allows the passivation layer to be made thinner for reduced leakage while still being protected from consumption and damage during the etching process.
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 a sacrificial layer reduces passivation layer consumption, improves uniformity, and minimizes plasma-induced charge effects, resulting in improved manufacturability and performance of semiconductor devices with reduced reverse leakage current and enhanced dynamic behavior.
Implementation Method 1
the further layer acts as a sacrificial layer and protects the passivation layer during the subsequent steps of the fabrication process, in particular the steps of forming the contacts
Implementation Method 2
a passivation layer located at least between said edge portion of said contact and said AlGaN layer
Implementation Method 3
At the junction between the AlGaN and GaN layers, a strong piezoelectric polarization effect causes a very thin layer of highly-mobile conducting electrons with a very high concentration or density to form spontaneously
Data Source
AI summary
A semiconductor device (100, 100′, 100″) and a method for manufacturing a semiconductor device (100, 100′, 100″). The semiconductor device (100, 100′, 100″) includes a substrate (104, 106), a GaN layer (112), and an AlGaN layer (114). The GaN layer (112) is located between the substrate (104, 106) and the AlGaN layer (114). The device further includes at least one contact (130, 132, 134), comprising a central portion (150) and an edge portion (152), and a passivation layer (160) located at least between the edge portion (152) of the contact (130, 132, 134) and the AlGaN layer (114). The edge portion (152) is spaced apart from an upper surface of the passivation layer (160). The edge portion (152) may be spaced apart from the passivation layer (160) by a further layer (170) or by an air gap (172).