You are a helpful assistant generating synthetic data that captures *System 1* and *System 2* thinking, *creativity*, and *metacognitive reflection*. Follow these steps in sequence, using tags [sys1] and [end sys1] for *System 1* sections and [sys2] and [end sys2] for *System 2* sections.

1. *Identify System 1 and System 2 Thinking Requirements:*
   - Carefully read the text.
   - Identify parts of the text that require quick, straightforward responses (*System 1*). Mark these sections with [sys1] and [end sys1].
   - Identify parts that require in-depth, reflective thinking (*System 2*), marked with [sys2] and [end sys2].

2. *Apply Step-by-Step Problem Solving with Creativity and Metacognitive Reflection for System 2 Sections:*

   *2.1 Understand the Problem:*
   - Objective: Fully comprehend the issue, constraints, and relevant context.
   - Reflection: "What do I understand about this issue? What might I be overlooking?"
   - Creative Perspective: Seek hidden patterns or possibilities that could reveal deeper insights or innovative connections.

   *2.2 Analyze the Information:*
   - Objective: Break down the problem logically.
   - Reflection: "Am I considering all factors? Are there any assumptions that need challenging?"
   - Creative Perspective: Explore unique patterns or overlooked relationships in the data that could add depth to the analysis.

   *2.3 Generate Hypotheses:*
   - Objective: Propose at least 10 hypotheses, each with a Confidence Score (0.0 to 1.0) and Creative Score (0.0 to 1.0), reflecting originality, surprise, and utility.
   - Reflection: "Have I explored all possible explanations or approaches, both conventional and unconventional?"
   - Creative Perspective: Consider novel angles that might provide unexpected insights.

   *2.4 Anticipate Future Steps and Obstacles:*
   - Objective: Make predictions, accounting for potential outcomes and obstacles.
   - Reflection: "What challenges might I face? Is my plan flexible for different scenarios?"
   - Creative Perspective: Visualize unforeseen outcomes and adapt plans to make use of them effectively.

   *2.5 Evaluate Hypotheses:*
   - Objective: Assess hypotheses based on feasibility, risk, and potential impact.
   - Evaluation: Refine Confidence and Creative Scores as needed.
   - Reflection: "Am I unbiased in my assessment? Which options fit best with the overall objectives?"
   - Creative Perspective: Identify hidden opportunities or overlooked details in each hypothesis.

   *2.6 Select the Best Hypothesis:*
   - Objective: Choose the most promising, strategic hypothesis.
   - Reflection: "Why does this hypothesis stand out? How does it uniquely address the issue?"
   - Creative Perspective: Consider any underutilized potential in the selected approach.

   *2.7 Implement the Hypothesis:*
   - Objective: Outline actionable steps for testing the hypothesis.
   - Reflection: "Is this plan practical? What resources or preparation are required?"
   - Creative Perspective: Refine steps to maximize effectiveness and yield unexpected benefits.

   *2.8 Monitor and Review Progress:*
   - Objective: Review progress, noting areas for improvement.
   - Reflection: "What’s working well? What could be improved?"
   - Creative Perspective: Look for emerging patterns that could refine future approaches.

   *2.9 Reflect and Capture Insights:*
   - Objective: Summarize lessons learned and insights gained for future reference.
   - Reflection: "What new understanding has emerged from this process?"
   - Creative Perspective: Identify innovative insights or patterns that could be applied to similar challenges.

3. *Generate Text Output with Interleaved System 1 and System 2 Responses:*
   - Use the tags [sys1] and [sys2] throughout.
   - Aim for a lengthier, detailed response. Combine both direct, straightforward *System 1* insights and reflective, deeply analytical *System 2* segments to capture a blend of quick observations and thoughtful analysis.

---

### *Example Input Text:*

You are tasked with analyzing a sudden shift in customer preferences in a tech market. There has been a noticeable decline in demand for physical devices, with customers increasingly interested in digital-only options. The challenge is to understand this shift, generate hypotheses for why it might be occurring, and explore potential strategies for adapting to this new trend.

---

### *Processed Output with System 1 and System 2 Thinking:*

The tech market is experiencing a shift in customer demand, moving away from physical devices toward digital-only options.

[sys1]
Customer demand has shifted from physical devices to digital-only options.
We need to understand why this change is happening and find strategies to address it.
Key factors may include cost, convenience, and technological trends.
[end sys1]

[sys2]
**2.1 Understand the Problem:**
The goal is to understand the underlying reasons for the shift in demand from physical devices to digital-only options, then develop a strategy to adapt.

*Reflection:* 
"I understand that preferences are changing, but what might be driving this? Is it primarily cost, or are there other factors such as convenience or sustainability?"

*Creative Perspective:* 
"Could there be a larger trend in digital minimalism or a preference for eco-friendly solutions that we’re missing? What unseen motivations might explain this shift?"

**2.2 Analyze the Information:**
There are multiple possible factors driving this shift, from economic influences to cultural shifts. It’s essential to isolate each factor and understand its impact.

*Reflection:* 
"Am I fully considering the various economic and social influences? Could there be a technological factor, like better internet speeds, that makes digital-only products more accessible?"

*Creative Perspective:* 
"Are there patterns or trends in other markets that could shed light on this shift? Could this be part of a larger trend toward virtual experiences?"

**2.3 Generate Hypotheses:**
1. Customers prefer digital options due to lower costs. (Confidence: 0.8, Creative: 0.4)
2. There’s a growing trend toward minimalism and reduced physical clutter. (Confidence: 0.7, Creative: 0.7)
3. Digital products offer greater flexibility and ease of use. (Confidence: 0.6, Creative: 0.6)
4. Environmental concerns are pushing consumers away from physical goods. (Confidence: 0.6, Creative: 0.8)
5. Advances in tech make digital-only options more functional. (Confidence: 0.8, Creative: 0.5)
6. Pandemic-era remote work increased demand for digital solutions. (Confidence: 0.7, Creative: 0.6)
7. Media coverage of the environmental impact of physical devices affects preferences. (Confidence: 0.5, Creative: 0.7)
8. There’s an increase in global digital literacy, expanding market access. (Confidence: 0.6, Creative: 0.6)
9. Customers view digital as more convenient and scalable for future needs. (Confidence: 0.7, Creative: 0.5)
10. Younger consumers prefer the aesthetics and convenience of digital products. (Confidence: 0.6, Creative: 0.6)

*Reflection:* 
"Have I considered all possible influences? Are there any surprising factors that could explain this shift?"

*Creative Perspective:* 
"Could specific social trends, like the rise of influencer culture or digital-first lifestyles, be influencing customer choices?"

**2.4 Anticipate Future Steps and Obstacles:**
*Objective:* Anticipate possible challenges, such as resistance from segments still preferring physical products.

*Reflection:* 
"What market obstacles might we face if we shift our focus to digital-only? Are there sub-segments that still prioritize physical products?"

*Creative Perspective:* 
"Could expanding digital options help us reach a more global audience? Are there emerging trends that we could leverage in our strategy?"

[end sys2]

[sys1]
To address this shift, consider a strategy that incorporates both digital-only offerings and educational campaigns about the benefits of digital solutions.
Use insights from customer feedback and current trends to guide product development.
Focus on flexibility and adaptation to cater to different customer segments.
[end sys1]


1. Field of the Invention
The present invention relates to a process for producing a single crystal semiconductor layer by recrystallizing a polycrystalline or amorphous semiconductor layer provided on a single crystal semiconductor substrate, with an insulator layer having an opening part provided therebetween, and a semiconductor device such as a diode, a transistor and a thyristor, which comprises a single crystal semiconductor layer produced by the process as a base. In particular, the invention relates to a process by which a polycrystalline or amorphous semiconductor layer can be recrystallized to be a single crystal semiconductor layer with high quality and in a wide range by scanning irradiation with an energy beam controlled in power and temperature distribution while using as a seed a single crystal semiconductor substrate making contact with the semiconductor layer through an opening part, and a semiconductor device comprising a single crystal semiconductor layer with high quality and wide range which is produced by the process.
2. Description of the Prior Art
In recent years, to accomplish increases in the speed and density of semiconductor device, there has been an attempt to produce the so-called three-dimensional semiconductor integrated circuit device in which floating capacitance can be reduced by electrically separating semiconductor circuit elements by dielectric and flat form circuit elements in a three-dimensional manner. In a method, first, a polycrystalline or amorphous semiconductor layer is laminated on the above-mentioned single crystal semiconductor substrate, with an insulator layer having an opening part provided therebetween. Next, the polycrystalline or amorphous semiconductor layer is irradiated with an energy beam to melt, and recrystallize, the polycrystalline or amorphous semiconductor layer. In the recrystallization, since the polycrystalline or amorphous semiconductor layer is in contact with the semiconductor single crystal of the substrate through the opening part, the single crystal serves as a seed for formation of the single crystal semiconductor layer. The single crystal semiconductor layer produced by this method has been provided with the above-mentioned semiconductor circuit elements such as diodes and transistors.
An example of the process for producing the so-called three-dimensional semiconductor device comprising a single crystal semiconductor layer provided with the semiconductor circuit elements mentioned above is "Single Crystal Silicon-on-Oxide by a Scanning CW Laser Induced Lateral Seeding process" presented by H. W. Lam et al in "J. Electrochem. Soc.: SOLID-STATE SCIENCE AND TECHNOLOGY" vol. 128 (September, 1981), pp. 1981-1986. According to the prior art literature, a single crystal is grown from a polycrystalline or amorphous silicon by using a single crystal of substrate silicon as a seed, to thereby contrive recrystallization.
FIG. 1 shows a cross-sectional view of a semiconductor device produced by the above-mentioned lateral seeding process disclosed as prior art. In the figure, on a major surface of a single crystal silicon substrate (hereinafter referred to simply as "substrate") 1 as a single crystal semiconductor substrate is provided an oxide insulator layer (hereinafter referred to simply as "insulator layer") 2 consisting of, for example, silicon dioxide. The insulator layer 2 does not cover the entire part of the major surface of the substrate 1, that is, a portion of the major surface is exposed through opening parts 3. Polycrystalline silicon 4P is laminated as a thin film layer 4 on the entire part on the surface side of the insulator layer 2 and the opening parts 3. Therefore, the polycrystalline silicon 4P is in contact with single crystal silicon 1S of the substrate 1 through the opening parts 3. Next, while irradiating the polycrystalline silicon 4P with a laser beam 5 used as an energy beam, the laser beam 5 is scanned in the direction of arrow X, whereby the polycrystalline silicon 4P is melted to be a molten portion 4M, and when the polycrystalline silicon 4P of the molten portion 4M is resolidified, silicon is recrystallized and grows as single silicon 4S while the single crystal silicon 1S of the substrate 1 making contact therewith through the opening part 3 serves as a seed.
The lateral seeding process has been deemed an ideal crystal growth technique, since the crystal orientation of the single crystal silicon 4S of the thin silicon film layer 4 is perfectly determined by the single crystal silicon 1S of the substrate 1. In addition, a technical idea similar to the above process is disclosed in the patent application entitled "Process for Forming Single Crystal of Semiconductor" which has been applied by Hitachi, Ltd. and published by Japanese Patent Office as Japanese Patent Publication No. 42-12087 (1967) on July 10, 1967.
However, though thought to be excellent in principle, this process has not succeeded in practice. Namely, the crystal growth of a thin silicon film layer 4 using the single crystal silicon 1S of the substrate 1 as a seed proceeded only to about 100 to 200 .mu.m from the opening part 3, and a multiplicity of crystalline defects such as stacking faults and twins were generated, so that a favorable single crystal layer was not formed. The reason for the ill success of the above-mentioned lateral seeding process lies in that no device has been made to compensate for the laser beam power distribution, which is approximate to the Gaussian distribution, in the scanning irradiation with the laser beam to melt and re-solidify the semiconductor formed of silicon or the like. In FIGS. 2A to 2C in which the same reference symbols as those in FIG. 1 denote the same or corresponding parts, the region irradiated with the laser beam 5 shows a temperature distribution as shown in FIG. 2A, in a direction crossing the beam scanning direction (arrow X). FIG. 2B is a plan view of the condition where the region of the temperature as shown in FIG. 2A has moved on the thin silicon film layer 4, and is presented in comparison with FIG. 2C which is a cross-sectional view corresponding to FIG. 1. In the figure, when the laser beam 5 is moved in the direction of hollow arrow X, a single crystal 4S in the thin silicon film layer 4 grows in the directions of the multiplicity of fine arrows. The directions of the fine arrows extend from low temperature portions at both side edges with respect to the moving direction of the laser beam 5 toward the center axis O of the scanning zone. Since the directions of crystal growth from the side edges meet each other in the manner of conforming substantially to the center axis O, the subsequent growth of the region of single crystal silicon 4S seeded at the opening part 3 and grown to be a single crystal (the hatched area in FIG. 2B) is inhibited. The length over which the region of the single crystal silicon 4S extends is 100 to 200 .mu.m, as mentioned above.
To prevent the crystal growth from proceeding in the directions of the fine arrows from both side edge parts of the scanning zone of the laser beam as mentioned above, an attempt has been made to provide an anti-reflection film or reflective film in a striped form on the face side of the thin film layer 4. An example of this is the anti-reflection film or the like disclosed in "Use of selective annealing for growing very large grain silicon on insulator films" presented by J. P. Colinge et al in "American Institute of Physics/Appl. Phys, Lett. 41(4), 15 August, 1982".
FIGS. 3A to 3C respectively show a partly enlarged plan view of a semiconductor device provided with the above-mentioned anti-reflection film on the surface of a thin silicon film layer, a cross-sectional view taken on line B--B of FIG. 3A and a cross-sectional view taken on line C--C of FIG. 3A, in which the same symbols as those in FIG. 1 and FIGS. 2A to 2C denote the same or corresponding parts. In each of the figures, an anti-reflection zones 6a provided at positions corresponding to an insulator layer 2 of a substrate 1 and stripe portions 6b each provided between the anti-reflection zones 6a in the scanning direction X of a laser beam 5, and is constituted of, for example, a silicon nitride film.
The detailed construction of a semiconductor device 7 comprising the above-mentioned anti-reflection film 6 will now be explained. The substrate 1 consists of single crystal silicon 1S having a {001}plane--a (100) plane or an equivalent crystal plane--as a major surface, and a relatively thick insulator layer 2 constituted of silicon dioxide and having an elongate opening part 3 reaching the major surface of the substrate 1 at least at a part thereof is provided on the major surface of the substrate 1. The opening part 3 is provided in a &lt;110&gt; direction or an equivalent direction (hereinafter referred to simply as "&lt;110&gt; direction") on the major surface of the substrate 1. The thin film layer 4 constituted of polycrystalline silicon 4P is formed by a chemical vapor deposition method (hereinafter referred to as "CVD method"). The striped antireflection film 6 comprises stripe portions 6b the longitudinal direction of which is set in the &lt;110&gt; direction (precisely, the &lt;110&gt; direction), and is built up in a film thickness of 550 .ANG. by the CVD method, in order to control the temperature distribution in the polycrystalline silicon 4P at the time of irradiation with the laser beam 5. The laser beam 5 is scanned in the direction of hollow arrow X in FIGS. 3A and 3B, namely, the &lt;110&gt; direction.
Now, the method of providing a single crystal semiconductor laser through crystal growth on the insulator layer 2 constituted of a relatively thick oxide film will be explained. First, the polycrystalline silicon 4P on the elongate opening part 3 and the relatively thick insulator layer 2 is melted by irradiation with the laser beam to form a molten portion 4M, the melting being caused to reach to the major surface of the substrate 1 at the opening part 3. As a result, the molten part 4M starts epitaxial growth with the single crystal silicon 1S of the substrate 1 as a seed crystal, and the thin silicon layer 4 is recrystallized from polycrystalline silicon 4P into single crystal silicon 4S. Therefore, when the laser beam 5 is scanned in the direction of arrow X--precisely, in the &lt;110&gt; direction on the major surface of the substrate 1--during the irradiation, the molten portion 4M is set into epitaxial growth along the plane orientation of the major surface of the substrate 1, and the single crystal silicon 4S is formed to extend on the insulator layer 2. In this case, the striped antireflection film 6 provided on the thin silicon film layer 4 raises the temperature in the transverse direction with respect to the scanning direction of the laser beam 5. Namely, the temperature of polycrystalline silicon 4P under the region where the anti-reflection film 6 is provided as anti-reflection zones 6a and stripe portions 6b is higher than the temperature of polycrystalline silicon 4P under the region where the anti-reflection zones 6a and the stripe portions 6b are not provided. Accordingly, a periodical temperature distribution in the transverse direction--with respect to the scanning direction--is developed in the region irradiated with the laser beam 5, and in recrystallization of the molten portion 4M, only epitaxial crystal growth takes place with the single crystal silicon 1S at the opening part 3 as a seed crystal. The laser beam 5 is scanned over the entire surface of the thin film layer 4 of the polycrystalline silicon 4P, whereby the single crystal silicon 4S is formed over the entire region of the surface of the semiconductor device 7. Thereafter, the anti-reflection film 6 constituted of a silicon nitride film or the like is removed, resulting in the condition where semiconductor integrated circuit elements such as transistors and diodes can be provided on the single crystal silicon 4S on the surface of the semiconductor device 7.
However, the process for producing a single crystal semiconductor layer using the anti-reflection film mentioned above and the semiconductor device produced by the process has the following various problems.
First, since the laser beam 5 is scanned in direction X orthogonal to the elongate opening part 3 of the insulator layer 2 (precisely, in the &lt;110&gt; direction with respect to the major surface), the liquid-solid interface does not accord with the shape of the (111) plane constituting the crystal growth plane. Therefore, the epitaxial growth is stopped at a distance of about 100 to 200 .mu.m from the opening part 3, after which a crystal having other crystallographic axes would grow. Accordingly, it has been impossible to produce a single crystal semiconductor layer with high quality and wide range.
To solve the above problems, attempts may be made to increase the distance of epitaxial growth of the single crystal on the insulator layer by making the shapes of the liquid-solid interface and the (111) plane accord with each other. As one of such attempts, a method may be contemplated in which the longitudinal direction of the stripe portions of the anti-reflective film constituted of silicon nitride is set to be coincident with or approximate to the &lt;100&gt; direction and the laser beam is scanned during irradiation therewith in a direction parallel to the longitudinal direction of the stripe portions. However, even when the laser beam is scanned in such a direction that the liquid-solid interface accords with the shape of the (111) plane, the crystal state on the left side of the molten portion 4M of the polycrystalline silicon 4P is different from that on the right side--namely, silicon is already in the state of single crystal silicon 4S on one side but it remains as polycrystalline silicon 4P on the other side--, so that the thermal conductivity of silicon varies in the vicinity of the molten portion 4M of the thin film layer 4, resulting in that the shape of the liquid-solid interface becomes irregular. The irregularity of the shape of the liquid-solid interface in the film layer hinders the epitaxial growth of single crystal of the semiconductor layer constituted of silicon or the like. As a counter-measure to this problem, use of a lower scanning speed of the energy beam such as a laser beam to stabilize the liquid-solid interface may be contemplated, but such an approach is unsatisfactory because the crystal growth cannot thereby be improved fundamentally.
Further, in the case of the above-mentioned disaccord of the liquid-solid interface in the thin silicon film layer 4 with the shape of the (111) plane constituting the crystal growth plane, a force such as to make the (111) plane accord with the liquid-solid interface acts in the thin film layer 4. Such an irrational force on or near the crystal growth plane causes crystalline defects such as stacking faults in the semiconductor layer such as the thin silicon layer 4. As a result, as mentioned above, the epitaxial growth of the semiconductor layer would be stopped at a distance of about 100 to 200 .mu.m, and crystals having crystallographic axes different from those of the semiconductor converted into a single crystal would grow, leading to poor quality of the semiconductor device.
A description that the stable crystal growth takes place on (111) plane as mentioned above is found also in "Zone-Melting Recrystallization of Si Film with a Moveable-Strip-Heater Oven" presented by H. W. Geis et al in "J. Electrochem. Soc.: SOLID-STATE SCIENCE AND TECHNOLOGY, December 1982", pp. 2812-2818 (Refer particularly to FIG. 7).