Metal-Insensitive Epitaxy via Passivation Layer
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Solution Overview
Problem
The semiconductor industry faces challenges in scaling down planar devices like MOSFETs due to high power dissipation and metal contamination, which introduces device defects and performance concerns, particularly in strained field effect transistors (FETs) with enhanced mobility.
Innovation Solution
A semiconductor structure and method that includes forming a passivation layer to isolate metal residuals from chlorine during subsequent operations, preventing metal-assisted silicon etching and using selective epitaxy growth to fill recesses with semiconductor material, thereby eliminating defects and enhancing device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scaling down planar devices like MOSFETs to increase device density, then functional density improves, but power dissipation increases and metal contamination causes device defects
Solution Approach 1:
A passivation layer is formed in advance to cover and isolate metal residuals from chlorine-based chemicals before subsequent fabrication steps. This preliminary protective action prevents metal-assisted silicon etching and device defects that would otherwise occur during scaling operations
Solution Approach 2:
The passivation layer acts as an intermediary barrier between metal residuals and chlorine-containing chemicals. This intermediate layer prevents direct harmful interaction between these two substances, eliminating the metal-assisted etching mechanism while allowing the scaling process to continue
2Ease of manufacture
If using chlorine-based chemicals in subsequent operations, then fabrication processes can proceed, but metal-assisted silicon etching occurs causing device defects
Solution Approach 1:
The passivation layer serves as a protective intermediary that allows chlorine-based fabrication processes to proceed while preventing direct contact between chlorine and metal residuals. This eliminates metal-assisted silicon etching without impeding the necessary fabrication steps
Solution Approach 2:
The passivation layer is applied in advance to counteract the harmful effect of metal-assisted etching. By pre-establishing this protective barrier, the patent prevents the adverse interaction between metal residuals and chlorine chemicals before it can occur during subsequent processing
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 solution effectively reduces defects and improves device performance by preventing metal-assisted silicon etching and ensuring the growth of semiconductor material in a crystalline structure, addressing the challenges of scaling down FETs while maintaining enhanced mobility.
Implementation Method 1
forming a passivation layer to isolate metal residuals from chlorine during subsequent operations, preventing metal-assisted silicon etching
Implementation Method 2
using selective epitaxy growth to fill recesses with semiconductor material, thereby eliminating defects and enhancing device performance
Data Source
AI summary
The present disclosure provides a semiconductor device structure in accordance with some embodiments. In some embodiments, the semiconductor device structure includes a semiconductor substrate of a first semiconductor material and having first recesses. The semiconductor device structure further includes a first gate stack formed on the semiconductor substrate and being adjacent the first recesses. In some examples, a passivation material layer of a second semiconductor material is formed in the first recesses. In some embodiments, first source and drain (S/D) features of a third semiconductor material are formed in the first recesses and are separated from the semiconductor substrate by the passivation material layer. In some cases, the passivation material layer is free of chlorine.