Germanium Layer Formation via Stacked Buffer Structure
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Solution Overview
Problem
Germanium layers or high germanium content silicon germanium layers formed on a silicon substrate often suffer from defects due to lattice mismatches, leading to increased leakage and strain, which existing germanium condensation processes may exacerbate by introducing extended defects.
Innovation Solution
A method involving a stacked structure with a silicate glass layer, a diffusion barrier layer, and an interfacial oxide layer is used, where a first semiconductor layer is converted into a higher germanium concentration layer through oxidation, with a capping oxide layer and controlled temperature processes to reduce strain and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If germanium layers or high germanium content silicon germanium layers are formed on a silicon substrate, then device performance can be improved, but defects and leakage increase due to lattice mismatches
Solution Approach 1:
The patent introduces a stacked structure comprising a silicate glass layer, diffusion barrier layer, and interfacial layer as intermediary layers between the silicon substrate and germanium layer. These intermediary layers act as buffer zones that accommodate lattice mismatches and prevent defect propagation, thereby enabling high-performance germanium devices while minimizing leakage and defects
Solution Approach 2:
The patent employs a composite stacked structure combining multiple materials (silicate glass, nitride diffusion barrier, oxide interfacial layer) with different properties. Each layer contributes specific functions: mechanical buffering, diffusion prevention, and interface stabilization, collectively resolving the lattice mismatch problem while maintaining device performance
2Object-affected harmful factors
If a germanium condensation process using oxidation is used to reduce defects, then defects due to lattice mismatches are reduced, but strain is built in germanium layers causing extended defects
Solution Approach 1:
The patent performs preliminary actions by forming the complete stacked structure (silicate glass layer, diffusion barrier layer, interfacial layer) before introducing germanium. This pre-prepared buffer structure is designed to accommodate and relax strain during subsequent germanium deposition and oxidation processes, preventing extended defects while still reducing lattice mismatch defects
Solution Approach 2:
The patent utilizes controlled oxidation parameters and temperature management during the germanium condensation process. By carefully controlling oxidation conditions and utilizing the thermal properties of the stacked structure, the process reduces lattice mismatch defects while the intermediary layers absorb and distribute strain, preventing extended defect formation
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
This approach results in germanium layers with reduced defects and strain, suitable for use in integrated circuit devices as channel layers or seed layers for III-V semiconductor materials, improving device performance by minimizing leakage and extending defect reduction.
Implementation Method 1
oxidizing the third semiconductor layer to drive germanium therein into the first semiconductor layer
Implementation Method 2
oxidizing the third semiconductor layer may be performed at a temperature higher than a reflow temperature of the silicate glass layer
Data Source
AI summary
Methods of forming a semiconductor layer including germanium with low defectivity are provided. The methods may include sequentially forming a silicate glass layer, a diffusion barrier layer including nitride and an interfacial layer including oxide on a substrate. The methods may also include forming a first semiconductor layer on the interfacial layer and converting a portion of the first semiconductor layer into a second semiconductor layer having a germanium concentration therein that is higher than a germanium concentration of the first semiconductor layer.