| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1994: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1993: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
The techniques demanded eagerly for highly effiecient thermoelectric device, i.e., in this case, 1) growth of GeSi bulk alloy with homogeneous composition, 2) control in electric ocnducton, and 3) device processes for GeSi alloy, have been developed.
1)The "yo-yo batch system", useful for mass-production of GeSi alloy substrates, has been developed, in which some Si substrates are placed in the yo-yo solute-feeding growth system. This system makes it possible to replace the middle Si substrate by a GeSi alloy plate after a sufficiently large number of yo-yo process. The experiments using a three-substrate system led successfully GeSi alloy plates with a thickness of 0.4mm after 62 yo-yo times.
The solute-feeding Czochralski method, developed for growing homogeneous bulk alloy, was also examined, and a GeSi bulk alloy with constant composition could be pulled at the constant temperature of 1050 C under Si solute-feeding conditions.
2)Based on the growth technique of n-type alloys from Sn solvent, developed in last year, the growth technique of p-type alloy has been investigated by adding Ga to Sn solvent. As a result, p-type alloys with hole concentration of 10^<18> to 10^<19> cm^<-3> became controllable.
3)To establish the GeSi device processes, p-n junctions were fabricated by liquid phase epitaxy. The diodes formed on the grown GeSi layr showed rectifying I-V characteristics cleary. The oxidation experiments of GeSi alloy were also carried out. The results, for example, such as the difference in oxidation speed of Si and Ge, will come in useful for advanced device technology.
Thus, the valuable results for progressing the researchs in thermo-electric devices were obtained by this project.
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