Stressed Semiconductor Blocks on SOI Substrate
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Solution Overview
Problem
Existing methods for producing semiconductor substrates with strained semiconductor zones are limited by the need for expensive and difficult SiGe growth, and require multiple steps to achieve both tensile and compressive stressing, which is unfavorable for P-type transistors.
Innovation Solution
A method involving the formation of amorphous semiconductor blocks with stress zones on a semiconductor-on-insulator substrate, where the lower region is amorphized and recrystallized using the upper crystalline region as a seed, allowing for simultaneous stressing and recrystallization, enabling better stress transfer and reducing the number of growth stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SiGe growth is used to produce strained semiconductor blocks, then tensile and compressive stress can be achieved, but the process becomes expensive and difficult to implement
Solution Approach 1:
The patent changes the material parameter from crystalline SiGe to amorphous stress-inducing layer, fundamentally altering the approach to stress induction. This allows stress to be achieved through the intrinsic stress of the amorphous layer rather than through lattice mismatch in crystalline SiGe, simplifying the manufacturing process while maintaining stress control capability
Solution Approach 2:
The patent uses an amorphous stress-inducing layer that can be deposited using standard techniques and then removed after transferring its stress to the semiconductor block. This disposable layer approach replaces the expensive and complex SiGe growth process with a simpler, more cost-effective method
2Adaptability or versatility
If multiple steps are used to achieve different stress states, then both tensile and compressive stressing can be achieved, but the number of process steps increases
Solution Approach 1:
The patent applies different amorphous stress-inducing layers to different local regions of the semiconductor substrate. By controlling the composition and deposition conditions of the amorphous layer in specific areas, both tensile and compressive stress states can be achieved simultaneously in different blocks without requiring multiple process sequences
Solution Approach 2:
The amorphous stress-inducing layer serves multiple functions: it induces stress through intrinsic stress, acts as a mask during processing, and can be selectively removed. This multi-functionality reduces the overall number of process steps required to achieve different stress states in different semiconductor blocks
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 method allows for the efficient creation of semiconductor blocks with different stress states on the same substrate, improving transistor performance by enhancing stress transfer and reducing process complexity and cost.
Implementation Method 1
b) recrystallizing the lower region of the first block and the region lower part of the second block by serving the upper region of crystalline material as a starting zone for a recrystallization front
Data Source
Figure 1A~1C
Figure 1D~1F
Figure 1G~2B
AI summary
A method for making a microelectronic device comprising: a) forming on an insulating layer of a semiconductor-on-insulator substrate, a first semiconductor block (12a) covered with a first stress zone (21) adapted to induce a compressive stress in said first block and a second semiconductor block (12b) covered with a second stress zone (22) adapted to induce a tensile stress in said second block, the first block and the second block each being formed of a lower region (13a, 13b) based on amorphous semiconductor material, covered with an upper region of crystalline semiconductor material (14a, 14b) in contact with one of said stress zones, b) recrystallizing said lower region (13a, 13b) of said first block and said second block using said upper region (14a, 14b) of crystalline material as a starting zone for a recrystallization front.