TECHNICAL FIELD

The present technique relates to solid-state imaging devices, solid-state imaging device manufacturing methods, and electronic apparatuses, and more particularly, to a solid-state imaging device having amplifying transistors in pixel drive circuits, a method of manufacturing the solid-state imaging device, and an electronic apparatus using the solid-state imaging device.

BACKGROUND ART

Among solid-state imaging devices, there are CMOS sensors. In a CMOS sensor that has pixel drive circuits for respective pixels, charges converted by the photoelectric conversion units of the respective pixels are amplified by amplifying transistors (source followers) included in the pixel drive circuits, and the amplified charges are output to vertical signal lines by a switching operation (see Non-Patent Document 1 below).

CITATION LIST

Non-Patent Document

Non-Patent Document 1: International Image Sensor Workshop 2007 (June 7-10, Ogunquit, Me., USA), “Modeling of the Temporal Pixel to Pixel Noise of CMOS Image Sensors”, pp. 219-222, [Search Date: Dec. 15, 2011], the Internet address (URL:http://www.imagesensors.org/Past%20Workshops/2007%20Workshop/2007%20Papers/056%20Leyris%20et%20al.pdf)

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

In recent years, solid-state imaging devices have become smaller in size and higher in the degree of integration, and accordingly, miniaturization of the elements that constitute the pixel drive circuits has been progressing. In CMOS sensors, however, RTS (Random Telegraph Signal) noise is generated due to miniaturization of amplifying transistors (source followers) as described in Non-Patent Document 1, and the noise forms blinking points that degrade display characteristics.

In view of the above, the present technique aims to provide a solid-state imaging device that can prevent generation of RTS noise due to miniaturization of amplifying transistors, and can achieve a smaller size and a higher degree of integration accordingly. The present technique also aims to provide a method of manufacturing such a solid-state imaging device, and an electronic apparatus using such a solid-state imaging device.

Solutions to Problems

A solid-state imaging device according to the present technique for achieving the above objects includes: a photoelectric conversion unit; a transfer gate that reads out charges from the photoelectric conversion unit; a floating diffusion from which the charges of the photoelectric conversion unit are read by an operation of the transfer gate; and an amplifying transistor of a fully-depleted type that is connected to the floating diffusion. More particularly, the amplifying transistor is of a fully-depleted type. Such an amplifying transistor includes a gate electrode extending in a direction perpendicular to convex strips formed by processing a surface layer of a semiconductor layer, for example.

A solid-state imaging device manufacturing method according to the present technique includes: forming convex strips by processing a surface layer of a semiconductor layer; forming a photoelectric conversion unit in the semiconductor layer; and forming a floating diffusion that is located in the surface layer of the semiconductor layer and is in the vicinity of the photoelectric conversion unit. The manufacturing method also includes: forming a transfer gate on the surface of the semiconductor layer between the photoelectric conversion unit and the floating diffusion, and forming a gate interconnect that is connected to the floating diffusion and extends in a direction perpendicular to the convex strips.

The present technique also provides an electronic apparatus that includes the above described solid-state imaging device.

In the solid-state imaging device having the above described structure, the amplifying transistor connected to the floating diffusion has a fully-depleted structure that operates as a transistor without containing any impurity in the channel portion. Accordingly, generation of RTS (Random Telegraph Signal) noise due to fluctuations of the channel impurity in amplifying transistors is prevented, and the amplifying transistors are miniaturized.

Effects of the Invention

As described above, according to the present technique, amplifying transistors of a fully-depleted type that can prevent generation of RTS noise are used. Accordingly, further miniaturization of amplifying transistors is realized, and a reduction in size and an increase in the degree of integration can be achieved in a solid-state imaging device. Also, a reduction in size can be achieved in an electronic apparatus that uses such a solid-state imaging device.

