This paper describes the development status of high-efficiency heterojunction with intrinsic thin-layer (HIT) solar cells at SANYO Electric. Presently, the conversion efficiency of our standard HIT solar cell has reached a level of 23.0% for a practical size of (100.4 cm(2)) substrate. On the other hand, we have developed special technologies for effectively using thinner substrates for HIT solar cells. Surprisingly, we have achieved a quite high open circuit voltage (V(oc)) of 743 mV, and a high conversion efficiency of 22.8% using only a 98-mu m-thick substrate. A 98-mu m-thick cell also exhibits a good temperature coefficient, and allows the thickness of the substrate to be reduced by more than 50% while maintaining its efficiency. These results suggest that the HIT solar cell has the potential to further improve cost-performance. (C) 2010 Elsevier B.V. All rights reserved.