Output amplifier for frame transfer visible light charge coupled device (CCD) and fabrication method of output amplifier

Abstract

The invention discloses an output amplifier for a frame transfer visible light charge coupled device (CCD). The output amplifier comprises a substrate layer, two source-drain regions, three gate mediums, a source-drain poly-silicon electrode, three phosphorus silicon glass layers, a baffle layer, a metal aluminum layer and ground. The invention also discloses a fabrication method of the output amplifier. The output amplifier has the beneficial effects that the output amplifier for the frame transfer visible light CCD and the fabrication method of the output amplifier are proposed, and by the scheme, the quality of the frame transformer visible light CCD can be effectively improved.

Description

technical field [0001] The invention relates to a CCD technology, in particular to an output amplifier and a manufacturing method for a frame transfer visible light CCD. Background technique [0002] Frame transfer visible light CCD is an important type of CCD. The amplifier on a common frame transfer visible light CCD is generally composed of a substrate layer, two source and drain regions, three gate dielectrics, source and drain polysilicon electrodes, a metal aluminum layer and a ground. structured as figure 2 As shown, there are some problems in the production of the prior art as follows: 1) The prior art generally adopts the thermal diffusion doping process to form the source and drain regions and the ground. Based on the characteristics of the thermal diffusion doping process, it can be seen that the thermal diffusion doping process The vertical diffusion speed and the lateral diffusion speed of the amplifier are almost the same. When the gate length of the amplifier...

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Problems solved by technology

[0002] Frame transfer visible light CCD is an important type of CCD. The amplifier on a common frame transfer visible light CCD is generally composed of a substrate layer, two source and drain regions, three gate dielectrics, source and drain polysilicon electrodes, a metal aluminum layer and a ground. structured as figure 2 As shown, there are some problems in the production of the prior art as follows: 1) The prior art generally adopts the thermal diffusion doping process to form the source and drain regions and the ground. Based on the characteristics of the thermal diffusion doping process, it can be seen that the thermal diffusion doping process The vertical diffusion speed and the lateral diffusion speed of the amplifier are almost the same. When the gate length of the amplifier is small, it is easy to cause source-drain punch-through and make the amplifier invalid. When making an amplifier with a small gate length, it is necessary to design something in the amplifier to prevent source-drain punch-through structure, which greatly increases the difficulty of making amplifiers with smaller gate lengths; 2) in the prior art, when making the metal aluminum layer, the wet etching process is generally used to etch the electrodes on the metal aluminum layer, based on the wet etching process It can be seen from the process characteristics that the vertical corrosion rate and the horizontal corrosion rate of the wet etching process are almost the same. When the metal aluminum layer is corroded downward, although there is photoresist protection in the lateral direction, the etching solution will also perform lateral corrosion, making the step position The thickness of the metal aluminum layer at the place becomes narrower, because the metal aluminum layer is generally formed by evaporation process, at the step position on the device, the bottom of the metal aluminum layer at the chamfer of the step is empty, and the corrosion solution is easy to penetrate in to make the metal aluminum layer There are broken bars at the step position, which makes it difficult to guarantee the DC reliability of the device; 3) The metal aluminum layer is in direct contact with the silicon material. Since aluminum diffuses quickly in silicon, it is easy to diffuse into the PN junction, especially the shallow junction PN junction , prone to source-drain aluminum puncture, resulting in PN junction failure, resulting in CCD imaging failure, causing device failure and scrapping

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