Solid state imaging device, method for producing the same, and portable electronic device
A method for producing a solid-state imaging device comprising a plurality of unit pixel sections, including a first unit pixel section, is provided. The method includes the steps of forming a first conductivity type well region of the first unit pixel section on a second conductivity type semiconductor layer provided on a first conductivity type semiconductor layer, the first conductivity type well region including a light receiving region for generating charges corresponding to an amount of light incident thereon and a charge transfer region capable of transferring the charges; and generating a charge accumulation region, for accumulating the charges generated in the light receiving region, in the charge transfer region. The step of forming the first conductivity type well region includes the step of implanting impurities such that the light receiving region and the charge transfer region in the first conductivity type well region have a substantially uniform impurity concentration.
1. A method for producing a solid-state imaging device including a plurality of unit pixel sections, the plurality of unit pixel sections including a first unit pixel section; the method comprising the steps of:
forming a first conductivity type well region of the first unit pixel section on a second conductivity type semiconductor layer provided on a first conductivity type semiconductor layer, the first conductivity type well region including a light receiving region for generating charges corresponding to an amount of light incident thereon and a charge transfer region capable of transferring the charges; and
generating a charge accumulation region, for accumulating the charges generated in the light receiving region, in the charge transfer region;
wherein the step of forming the first conductivity type well region includes the step of implanting impurities such that the light receiving region and the charge transfer region in the first conductivity type well region have a substantially uniform impurity concentration.
2. A method according to claim 1 , wherein the step of forming the charge accumulation region includes the step of implanting impurities such that the charge accumulation region has a higher impurity concentration than the impurity concentration of the first conductivity type well region.
3. A method according to claim 1 , wherein:
the plurality of unit pixel sections further include a second unit pixel section provided adjacent to the first unit pixel section; and
the step of forming the first conductivity type well region includes the step of defining the first conductivity type well region by forming a well separation region in a border area between the first unit pixel section and the second unit pixel section.
4. A method according to claim 3 , wherein the step of defining the first conductivity type well region includes the step of implanting second conductivity type impurities into the well separation region.
5. A method according to claim 3 , wherein the step of defining the first conductivity type well region includes the step of forming a field insulating layer in the well separation region by thermal oxidation.
6. A method according to claim 3 , wherein the step of defining the first conductivity type well region includes the step of implanting second conductivity type impurities into the well separation region using a mask pattern layer.