Microwave Annealing for Polycrystalline Semiconductor Grain Growth
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Solution Overview
Problem
Conventional heat treatment methods for crystallizing amorphous Si and SiGe thin films in three-dimensional memory devices result in small grain diameters, leading to low carrier mobility and characteristic deterioration in peripheral transistors, and are complex and time-consuming.
Innovation Solution
The method involves annealing amorphous semiconductor films using microwave irradiation to form polycrystalline semiconductor films with larger grain diameters, achieving higher crystallization growth rates and lower temperature processing, thereby improving carrier mobility and reducing transistor deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional furnace annealing or lamp annealing is used to crystallize amorphous Si and SiGe thin films, then the films can be transformed into polycrystalline thin films, but the grain diameters become small and carrier mobility becomes low
Solution Approach 1:
The patent changes the heating method from conventional thermal annealing to microwave irradiation, fundamentally altering the physical parameters of the crystallization process. This enables crystallization at lower temperatures (reducing thermal damage) while achieving larger grain diameters and higher carrier mobility through non-thermal microwave effects that promote grain growth
Solution Approach 2:
The patent replaces the conventional thermal field (furnace annealing) with an electromagnetic field (microwave irradiation). This substitution allows for selective heating and crystallization without the need for high-temperature thermal environments, thereby achieving better grain structure and carrier mobility
2Stability of the object's composition
If high temperature heat treatment is applied to crystallize amorphous thin films, then crystallization can be achieved, but characteristic deterioration occurs in peripheral transistors
Solution Approach 1:
The patent fundamentally changes the crystallization parameter from temperature-dependent thermal annealing to microwave-frequency electromagnetic irradiation. This enables crystallization to occur at lower temperatures, preventing thermal damage to peripheral transistors while still achieving complete crystallization of the amorphous thin films
3Manufacturing precision
If solid-phase growth using Ge crystal as nucleus is used to form large grain diameter Si crystal, then large grain diameter can be achieved, but the process becomes complicated and time-consuming
Solution Approach 1:
The patent replaces the complex solid-phase growth method requiring Ge crystal nuclei with direct microwave-induced crystallization. This substitution eliminates the need for preparing Ge nuclei and complex process control, achieving large grain diameters through a simpler, more direct microwave annealing process
Solution Approach 2:
The patent uses microwave radiation as an intermediary energy source that directly promotes crystallization and grain growth without requiring intermediate Ge crystal nuclei. The microwave energy acts as a mediator that transforms amorphous material directly into large-grain polycrystalline structure, bypassing the complex nucleation process
4Manufacturing precision
If solid-phase growth using Ge crystal as nucleus is used, then large grain diameter Si crystal can be formed, but it takes long time for crystallization
Solution Approach 1:
The patent changes the energy input method from thermal diffusion-based solid-phase growth to microwave-driven crystallization. This parameter change dramatically accelerates the crystallization process while maintaining or enhancing grain diameter, reducing processing time significantly compared to conventional methods
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 allows for the formation of semiconductor devices with high channel mobility and improved performance by crystallizing amorphous films at lower temperatures and in shorter times compared to traditional furnace annealing, while suppressing characteristic deterioration in peripheral transistors.
Implementation Method 1
annealing the amorphous semiconductor film by irradiating the substrate with a microwave to form a polycrystalline semiconductor film from the amorphous semiconductor film
Implementation Method 2
annealing the amorphous semiconductor film by irradiating the substrate with a microwave
Implementation Method 3
crystallizing the amorphous Si film by solid-phase growth using a Ge crystal in contact with the amorphous Si film as a nucleus
Data Source
AI summary
In one embodiment, a method of manufacturing a semiconductor device includes forming an amorphous semiconductor film on a substrate. The method further includes annealing the amorphous semiconductor film by irradiating the substrate with a microwave to form a polycrystalline semiconductor film from the amorphous semiconductor film. The method further includes forming a transistor whose channel is the polycrystalline semiconductor film.