Localized Single-Crystal Germanium-on-Insulator Integration
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Solution Overview
Problem
Current methods cannot produce a single-crystal semiconductor layer on a dielectric layer with localized integration of germanium-on-insulator zones on a silicon substrate, limiting the co-integration of silicon and germanium technologies in integrated circuits.
Innovation Solution
A process involving reduced-pressure chemical vapour deposition (RPCVD) to form a partially crystalline germanium layer on a silicon substrate, followed by recrystallization annealing and deposition of an amorphous or partially crystalline germanium layer on the dielectric layer, achieving a single-crystal germanium-on-insulator layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional ion implantation and fracture processes are used to produce germanium-on-insulator wafers, then entire germanium-on-insulator wafers can be produced, but localized integration of germanium zones on silicon substrate cannot be achieved
Solution Approach 1:
The patent applies local quality by enabling different regions of the substrate to have different semiconductor materials (germanium in specific zones, silicon elsewhere) through localized deposition and crystallization processes. The dielectric layer with openings allows germanium to be deposited only in specific local areas, creating zones with different material properties on the same substrate.
Solution Approach 2:
The process segments the substrate into different functional zones by using a dielectric layer with patterned openings. This allows separate germanium-on-insulator regions to be created on a silicon substrate, enabling co-integration of different semiconductor technologies in distinct areas of the same wafer.
2Reliability
If entire germanium-on-insulator wafers are produced using ion implantation, then germanium technology can be implemented, but cost increases due to germanium being a costly and less abundant material
Solution Approach 1:
The patent reduces germanium consumption by applying it only where needed - in specific zones defined by the dielectric layer openings - rather than covering the entire substrate. This localized approach maintains device performance in germanium regions while minimizing overall germanium usage and cost.
Solution Approach 2:
The process uses partial action by depositing germanium only in the necessary portions of the substrate rather than uniformly across the entire surface. This partial deposition strategy achieves the required device performance while reducing material consumption and cost.
3Manufacturing precision
If RPCVD is used to form partially crystalline germanium layer followed by recrystallization annealing, then single-crystal germanium-on-insulator layers can be produced locally, but process complexity increases
Solution Approach 1:
The process uses preliminary action by first forming a partially crystalline germanium layer through RPCVD before performing recrystallization annealing. This preliminary deposition creates a structured base layer that facilitates subsequent complete crystallization, ensuring high-quality single-crystal formation through controlled sequential steps.
Solution Approach 2:
The patent exploits phase transitions by controlling the crystallization process through temperature cycles. The RPCVD deposits a partially crystalline phase that is then transformed into a complete single-crystal phase through recrystallization annealing, utilizing controlled phase changes to achieve the desired material structure.
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
Enables the localized production of single-crystal germanium-on-insulator layers, allowing for the integration of both silicon and germanium technologies in the same integrated circuit, reducing germanium usage and costs, and enabling the production of transistors on both germanium-on-insulator and silicon-on-insulator substrates.
Implementation Method 1
reduced-pressure chemical vapour deposition (RPCVD) to form a partially crystalline germanium layer
Implementation Method 2
recrystallization annealing of the first material
Implementation Method 3
recrystallization annealing
Data Source
AI summary
The process relates to the production of a layer of a single-crystal first material on a second material. The second material has at least one aperture exposing a surface portion of a single-crystal third material. The process generally includes forming an at least partially crystalline first layer of said first material on said surface portion of the third material. Then, an amorphous or partially crystalline second layer of the first material is formed on the at least partially crystalline first layer of the first material and on one part of the second material that is around said aperture. Finally, the process includes recrystallization annealing of the first material. Thus, it is possible to produce, within one and the same wafer, either transistors on a germanium-on-insulator substrate with transistors on a silicon-on-insulator substrate, or transistors on a germanium-on-insulator substrate with transistors on a silicon substrate.