Semiconductor device, method of manufacturing the same, and solid-state image sensor

1. A method of manufacturing a semiconductor device, comprising the steps of:

providing a substrate including a semiconductor portion, a non-porous semiconductor layer, and a porous semiconductor layer arranged between the semiconductor portion and the non-porous semiconductor layer;

forming a porous oxide layer by oxidizing the porous semiconductor layer of the substrate provided by the step of providing the substrate;

forming a bonded substrate by bonding a supporting substrate to a surface, on a side of the non-porous semiconductor layer, of the substrate in which the porous oxide layer is formed; and

separating the semiconductor portion from the bonded substrate by utilizing the porous oxide layer,

wherein the step of providing the substrate includes the step of forming, by ion implantation, an impurity semiconductor region which has an exposed surface and extends through the non-porous semiconductor layer and reaches the semiconductor portion.

2. The method according to claim 1 , wherein

the step of providing the substrate includes the step of forming an impurity semiconductor layer to serve as the non-porous semiconductor layer on a semiconductor member,

the step of forming the impurity semiconductor layer is performed such that the impurity semiconductor region is formed in the impurity semiconductor layer, and

the step of providing the substrate further includes anodizing, through the exposed surface of the impurity semiconductor region, the impurity semiconductor region and part of the semiconductor member to change the impurity semiconductor region and the part of the semiconductor member into a porous structure such that the semiconductor portion is formed by another part of the semiconductor member, and

wherein the semiconductor member and the impurity semiconductor region have a first conductivity type, and the impurity semiconductor layer has a second conductivity type different from the first conductivity type.

3. The method according to claim 1 , wherein

the step of providing the substrate includes the steps of

forming a first impurity semiconductor layer on the semiconductor portion, and

forming a second impurity semiconductor layer on the first impurity semiconductor layer,

the step of forming the impurity semiconductor region is performed such that a partial region of the second impurity semiconductor layer is transformed into the impurity semiconductor region having a conductivity type identical to a conductivity type of the first impurity semiconductor layer by implanting an impurity into the partial region of the second impurity semiconductor layer, and

the step of providing the substrate further includes anodizing, through the exposed surface of the impurity semiconductor region, the impurity semiconductor region and the first impurity semiconductor layer to change the impurity semiconductor region and the first impurity semiconductor layer into a porous structure.

4. The method according to claim 2 , wherein the porous semiconductor layer provided in the step of providing the substrate includes a first porous semiconductor layer, and a second porous semiconductor layer having a pore density different from a pore density of the first porous semiconductor layer.