GaN HEMT Etch Protection Layer for Uniformity
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Solution Overview
Problem
GaN-based HEMTs are adversely affected by manufacturing etch processes, leading to worse electrical performance and uniformity issues.
Innovation Solution
A method involving the formation of a semiconductor device with a substrate, buffer, channel, and barrier layers, along with doped compound semiconductor, etch stop, and dielectric layers, where an etch protection layer is used to mitigate damage during etching processes, and a gate metal layer is formed to fill openings, ensuring protection and improved uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If etch process is performed to manufacture HEMT, then device structure is formed, but damage to critical layers and uniformity deteriorates
Solution Approach 1:
An etch protection layer is introduced as an intermediary between the etch process and the critical semiconductor layers. This protection layer is formed on the dielectric layer before etching, preventing direct contact between the etchant and underlying sensitive structures, thereby reducing damage and improving uniformity while still allowing the etch process to form the necessary device structure.
Solution Approach 2:
The etch protection layer is formed in advance before the etch process is performed. This preliminary action prepares the structure to withstand the subsequent etching, ensuring that critical layers are protected from damage before the actual structure formation occurs.
2Ease of manufacture
If etch process is performed to manufacture HEMT, then device structure is formed, but electrical performance deteriorates
Solution Approach 1:
The etch protection layer serves as a mediator that shields critical layers during the etch process. By preventing direct exposure to harsh etchants, the protection layer preserves the electrical properties of underlying layers while still allowing the etch process to create the necessary device structure.
Solution Approach 2:
The etch protection layer provides beforehand cushioning by being positioned between the etch process and sensitive semiconductor layers. This cushioning effect absorbs or mitigates the harmful effects of the etch process on electrical performance before damage can occur to critical structures.
3Manufacturing precision
If multiple layers are formed to protect critical structures, then damage during etching is reduced, but device complexity increases
Solution Approach 1:
The etch protection layer is applied selectively only where needed - specifically on the dielectric layer in regions that require protection during etching. This localized approach provides necessary protection without adding complexity to the entire device structure, maintaining manufacturing precision only where critical.
Data Source
AI summary
A method of forming a semiconductor device includes: providing a substrate, wherein a buffer layer, a channel layer, and a barrier layer are sequentially formed on the substrate; forming a doped compound semiconductor layer on a portion of the barrier layer; forming a first etch stop layer on the doped compound semiconductor layer; forming a second etch stop layer on the first etch stop layer; forming a first dielectric layer on the second etch stop layer; forming an etch protection layer on the first dielectric layer; performing a first etch process to form a recess in the first dielectric layer; performing a second etch process to form an opening exposing a portion of the second etch stop layer; performing a removal process to remove remaining portions of the etch protection layer on the first dielectric layer; and forming a gate metal layer to fill the opening.