Abstract: This solar cell element, which is increased in the conversion efficiency due to improved effect of passivation, includes a semiconductor substrate in which a p-type first semiconductor region and an n-type second semiconductor region are stacked such that the first semiconductor region is located nearmost a first principal surface side and the second semiconductor region is located nearmost a second principal surface side; and a first passivation film containing aluminum oxide and arranged on the first principal surface side of the first semiconductor region. In the inside of the first passivation film of the solar cell element, the first ratio obtained by dividing the aluminum atomic density by the oxygen atomic density is 0.613 or more and less than 0.667 and the second ratio obtained by dividing the sum of the aluminum atomic density and the hydrogen atomic density by the oxygen atomic density is 0.667 or more and less than 0.786.

Abstract: This solar cell element, which is increased in the conversion efficiency due to improved effect of passivation, includes a semiconductor substrate in which a p-type first semiconductor region and an n-type second semiconductor region are stacked such that the first semiconductor region is located nearmost a first principal surface side and the second semiconductor region is located nearmost a second principal surface side; and a first passivation film containing aluminum oxide and arranged on the first principal surface side of the first semiconductor region. In the inside of the first passivation film of the solar cell element, the first ratio obtained by dividing the aluminum atomic density by the oxygen atomic density is 0.613 or more and less than 0.667 and the second ratio obtained by dividing the sum of the aluminum atomic density and the hydrogen atomic density by the oxygen atomic density is 0.667 or more and less than 0.786.

Abstract: [Object] To provide a method for manufacturing a solar cell element including a semiconductor substrate that includes a high-concentration dopant layer located near the surface of the semiconductor substrate and a low-concentration dopant layer located more inside the semiconductor substrate than the high-concentration dopant layer. [Solving Means] A method includes heating a semiconductor substrate having a first conductivity type in a first atmosphere which contains a dopant having a second conductivity type and which has a first dopant concentration; heating in a second atmosphere the semiconductor substrate heated in the first atmosphere, the second atmosphere having a second dopant concentration less than the first dopant concentration; and heating in a third atmosphere the semiconductor substrate heated in the second atmosphere, the third atmosphere having a third dopant concentration greater than the second dopant concentration.

Abstract: Disclosed is a method for surface-treating a semiconductor substrate to thereby reduce loss of minority carriers caused by surface recombination and improve the lifetime. In the method, a semiconductor substrate is prepared. An acid additive and an alkaline additive are added to water to obtain an aqueous solution having a pH of not more than 7. The aqueous solution comprises no hydrofluoric acid. A dangling bond at a surface of the semiconductor substrate is hydrogen-terminated. The surface, at which the dangling bond has been hydrogen-terminated, is brought into contact with the aqueous solution.

Abstract: [Object] To provide a method for manufacturing a solar cell element including a semiconductor substrate that includes a high-concentration dopant layer located near the surface of the semiconductor substrate and a low-concentration dopant layer located more inside the semiconductor substrate than the high-concentration dopant layer [Solving Means] A method includes' heating a semiconductor substrate having a first conductivity type in a first atmosphere which contains a dopant having a second conductivity type and which has a first dopant concentration; heating in a second atmosphere the semiconductor substrate heated in the first atmosphere, the second atmosphere having a second dopant concentration less than the first dopant concentration; and heating in a third atmosphere the semiconductor substrate heated in the second atmosphere, the third atmosphere having a third dopant concentration greater than the second dopant concentration.