| Project/Area Number |
60550066
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
材料力学
|
|---|
| Research Institution | Toyama University |
|---|
Principal Investigator |
IWAKI Toshihiro Toyama University, Faculty of Engineering, 工学部, 講師 (90019191)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Nobuyuki Toyama University, Faculty of Engineering, 工学部, 教授 (50019204)
|
|---|
| Project Period (FY) |
1985 – 1986
|
| Project Status |
Completed (Fiscal Year 1986)
|
| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1985: ¥1,300,000 (Direct Cost: ¥1,300,000)
|
|---|
| Keywords | Crystal Growth / Semiconductor / Dislocation / Czochralski Technique / Thermal Stress / Residual Stress / 熱弾性論 |
|---|
| Research Abstract |
1. Theoretical solutions of thermal and residual stresses: The theoretical solutions of thermal stress during growth and residual stress after growth in a Czochralski-grown semiconducting crystal are obtained by using an isotropic thermoelastic model. It is assumed that a finite cylindrical crystal is withdrawn with a constant velocity and the stress components vanish at the interface.
2. Investigation of growth conditions : About fifty experimental results of <III> - <V> compounds are collected from journals and preprints. The most typical condition is obtained. The transmission X-ray topographs of the compounds and the photographs of etch pit pattern in the wafer are also collected. Some features are seen in them.
3. Numerical calculation: We get the following results from the numerical calculation. (1) The thermal and residual stresses are affected strongly by the Biot number. (2) The highest thermal stress is produced at the periphery near the solid-liquid interface. (3) The thermal and residual stresses are almost independent of the crystal length when the length is larger than two times diameters.
4. Dislocation distribution: The resolved shear stresses in an fcc single crystal are calculated for the <100> and <111> growth directions. The speculated dislocation array patterns are obtained from the resolved shear stresses by using the Penning's conception. The patterns are compared with the experimental ones. We get the following results. (1) The speculated dislocation array patterns agree well with those observed in GaAs and InP crystals. (2) In order to grow a dislocation-free crystal, it is necessary to reduce the thermal and residual stresses. The small Biot number is required for the reduction. (3) It is useful for the small Biot number to use a thick encapsulant and an after heater.
|
