Michihiko Takase

Plasma doping for silicon

Very shallow and dense doping was realized by using the plasma doping method. This method was applied to fabricate diodes and MOS transistors with photo-resist as a mask material. This method is likely to be an alternative to ion implantation due to its properties of low energy and high throughput. The brief history of plasma doping is also reviewed.

Thin concentrator photovoltaic module with micro-solar cells which are mounted by self-align method using surface tension of melted solder

We are developing a thin and lightweight CPV module using small size lens system made from poly methyl methacrylate (PMMA) with a short focal length and micro-solar cells to decrease the transporting and the installing costs of CPV systems. In order to achieve high conversion efficiency in CPV modules using micro-solar cells, the micro-solar cells need to be mounted accurately to the irradiated region of the concentrated sunlight. In this study, we have successfully developed self-align method thanks to the surface tension of the melted solder even utilizing commercially available surface-mounting technology (SMT). Solar cells were self-aligned to the specified positions of the circuit board by this self-align method with accuracy within ±10 µm. We actually fabricated CPV modules using this self-align method and demonstrated high conversion efficiency of our CPV module.