SOLID-STATE IMAGING ELEMENT AND METHOD FOR MANUFACTURING THE SAME

• Main Authors: HIROSE YOHEI, HONJO RYOKO, KIMIZUKA NAOHIKO, KATO AKIHIKO, BABA KOICHI, KUROBE TOSHIHIRO, TOYOFUKU TAKUYA, KATAOKA TOYOTAKA
• Format: Patent
• Language: English; Japanese
• Published: 07.02.2024
• Subjects: BASIC ELECTRIC ELEMENTS; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; SEMICONDUCTOR DEVICES

To provide a solid-state imaging element, capable of increasing the channel area of a pixel transistor and reducing the parasitic capacitance of a gate.SOLUTION: A solid-state imaging element including a pixel for performing photoelectric conversion includes: a substrate on which the pixel is provided: a first transistor including a first gate electrode part which is provided in the pixel and which is embedded in a first direction oriented from a first surface of the substrate toward a second surface of the substrate on the opposite side to the first surface; a first gate insulating film provided between an active region of the substrate in which the channel of the first transistor is formed, and a first side surface of the first gate electrode part facing the active region; and a first insulating film which is provided on a second side surface of the first gate electrode part other than the first side surface and which is thicker than the first gate insulating film. The depth of the first insulating film from the first surface toward the second surface of the substrate is substantially the same as or greater than the depth of the first gate electrode part, and in a cross section in the first direction, the width of an upper surface of the first gate electrode part is greater than the width of a bottom surface of the first gate electrode part.SELECTED DRAWING: Figure 4A 【課題】画素トランジスタのチャネル面積を増大させ、ゲートの寄生容量を低減可能な固体撮像素子を提供する。【解決手段】固体撮像素子は、光電変換する画素を備えた固体撮像素子であり、画素が設けられた基板と、画素に設けられ基板の第１面から第１面に対して反対側の基板の第２面へ向かう第１方向に埋め込まれた第１ゲート電極部分を備える第１トランジスタと、基板のうち第１トランジスタのチャネルが形成される活性領域と該活性領域に対向する第１ゲート電極部分の第１側面との間に設けられた第１ゲート絶縁膜と、第１側面以外の第１ゲート電極部分の第２側面に設けられ、第１ゲート絶縁膜よりも厚い第１絶縁膜とを備え、基板の第１面から第２面への第１絶縁膜の深さは、第１ゲート電極部分の深さとほぼ同じかあるいはそれより深く、第１方向の断面において、第１ゲート電極部分の上面の幅は、該第１ゲート電極部分の底面の幅よりも広い。【選択図】図４Ａ