Solid-state imaging device, production method thereof, and electronic device

Abstract

Disclosed is a solid-state imaging device which includes a pixel section, a peripheral circuit section, a first isolation region formed with a STI structure on a semiconductor substrate in the peripheral circuit section, and a second isolation region formed with the STI structure on the semiconductor substrate in the pixel section. The portion of the second isolation region buried into the semiconductor substrate is shallower than the portion buried into the semiconductor substrate of the first isolation region, and the height of the upper face of the second isolation region is equal to that of the first isolation region. A method of producing the solid-state imaging device and an electronic device provided with the solid-state imaging devices are also disclosed.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The invention generally relates to solid-state imaging devices, production methods thereof, and electronic devices provided with the solid-state imaging devices.[0003]2. Description of the Related Art[0004]Solid-state imaging devices are broadly classified into amplification type solid-state imaging devices, which are typically illustrated by CMOS (complementary metal-oxide semiconductor) image sensors, and charge transfer type imaging devices, which are typified by CCD (charge-coupled device) image sensors. The solid-state imaging devices have been used extensively in digital still cameras, digital camcorders, etc. In addition, as solid-state imaging devices mounted in mobile devices such as cellular phones with camera, PDA (personal digital assistant), etc., CMOS image sensors are used more frequently in recent years owing to relatively low source voltages and low power consumption characteristics among others.[0005]I...

AI Technical Summary

Benefits of technology

[0012]In view of the abovementioned and other difficulties, the present invention provides a solid-state imaging device that enables reducing the number of production processes and improving pixel characteristics including the sensitivity, and a production method thereof. In addition, this invention provides an electronic device incorporating the solid-state imaging device.

[0023]According to an embodiment of the present invention, therefore, the reduction of processes and the improvement in the pixel characteristic including sensitivity can be achieved.

Problems solved by technology

With regard to isolation regions in the solid-state imaging device, the former of the abovementioned structures, which forms the regions with the same STI structure in both the pixel section and the peripheral circuit section, is known to have a problem of increasing white spots.

Namely, since the STI isolation regions in the pixel section are formed deep into the semiconductor substrate similarly to the STI isolation regions in the peripheral circuit section, the effects of stresses and damages exerted onto the photodiode increase, and this results in the increase of white spots.

However, in this case, there is a problem of increasing the number of processes, since the formation of the abovementioned diffusion region has to be included in addition to the processes of forming the isolation region 125 with the STI structure in the peripheral circuit section 104.

When the polysilicon residue 133a is formed, several adverse effects may arise such as short circuit failures between neighboring gate electrodes 131 of the pixel transistors and defects of imaging characteristics.

Moreover, with the structure shown in FIG. 1, since the protrusion height h4 from the substrate is large for the insulator layer constituting the isolation region in the pixel section, the distance L1 between the photodiode and the on-chip micro-lens tends to become large, which is disadvantageous to the condensing efficiency and results in the decrease in the sensor sensitivity.

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