SOLID STATE IMAGE PICKUP DEVICE AND SOLID STATE IMAGE PICKUP DEVICE MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To provide a solid state image pickup device and a solid state image pickup device manufacturing method which can simplify a manufacturing process.SOLUTION: A solid state image pickup device according to an embodiment comprises a plurality of photoelectric conversion elements, a field effect transistor, trenches and a P-type impurity diffusion region. The plurality of photoelectric conversion elements are arranged two-dimensionally in a semiconductor layer. The field effect transistor has N-type source and drain on a surface side of the semiconductor layer. The trenches pierce the semiconductor layer from a surface to a rear face to surround respective photoelectric conversion element and each of which has a width increasing with the increasing distance from the surface of the semiconductor layer toward a position at a predetermined depth and not increasing at a position deeper than the position at the predetermined depth. The P-type impurity diffusion region is provided in a lateral face of the trench and has a P-type impurity concentration at a portion of the semiconductor layer from the surface to the position at the predetermined depth is lower than a P-type impurity concentration at a portion deeper than the position at the predetermined depth.SELECTED DRAWING: Figure 3 【課題】製造工程を簡略化することができる固体撮像装置および固体撮像装置の製造方法を提供すること。【解決手段】実施形態に係る固体撮像装置は、複数の光電変換素子と、電界効果トランジスタと、トレンチと、Ｐ型の不純物拡散領域とを備える。複数の光電変換素子は、半導体層に２次元に配列される。電界効果トランジスタは、半導体層における表面側にＮ型のソースおよびドレインを有する。トレンチは、半導体層の表裏を貫通して各光電変換素子を囲み、半導体層の表面から所定深さ位置へ向かうにつれて幅が拡大し、所定深さ位置よりも深い位置では幅が拡大しない。Ｐ型の不純物拡散領域は、トレンチの側面内に設けられ、半導体層の表面から所定深さ位置までの部位におけるＰ型の不純物濃度が、所定深さ位置よりも深い部位におけるＰ型の不純物濃度よりも低い。【選択図】図３