Charge transfer device, process for its manufacture, and method of driving the device

A charge transfer device, comprising:

• a semiconductor substrate of a certain conductivity type,
• a first diffusion layer of a reverse conductivity type formed on said semiconductor substrate,
• a second diffusion layer of the reverse conductivity type formed in said first diffusion layer,
• an insulation film formed above said semiconductor substrate, and
• first and second transfer electrodes formed on said insulating film, wherein the length of said first transfer electrode is longer than the length of said second transfer electrode,
• wherein at least one of said first transfer electrodes is formed above said second diffusion layer, and said first diffusion layer is formed below one of said second transfer electrodes,
• the ratio of said first transfer electrode and said second transfer electrode in width is between 1.6 and 4.0, and
• the charge transfer device is four phase driven,
• wherein the ratio of impurity concentration of said first diffusion layer and second diffusion layer is about 1.3 times.

A charge transfer device, comprising:

• a semiconductor substrate of a certain conductivity type,
• a first diffusion layer of a reverse conductivity type formed on said semiconductor substrate,
• a second diffusion layer of the reverse conductivity type formed in said first diffusion layer,
• an insulation film formed above said semiconductor substrate, and
• first and second transfer electrodes formed on said insulation film, wherein the length of said first transfer electrode is longer than the length of said second transfer electrode,
• wherein at least one of said first transfer electrodes is formed above said second diffusion layer, and said first diffusion layer is formed below one of said second transfer electrodes,
• the ratio of said first transfer electrode and said second transfer electrode in width is between 1.6 and 4.0, and
• the charge transfer device is four phase driven,
• wherein the channel potential formed on the surface of said semiconductor substrate is higher in said first diffusion layer than in said second diffusion layer.

A charge transfer device, comprising:

• a semiconductor substrate of a certain conductivity type,
• a first diffusion layer of a reverse conductivity type formed on said semiconductor substrate,
• a second diffusion layer of the reverse conductivity type formed in said first diffusion layer,
• an insulation film formed above said semiconductor substrate, and
• first and second transfer electrodes formed on said insulation film, wherein the length of said first transfer electrode is longer than the length of said second transfer electrode,
• wherein at least one of said first transfer electrodes is formed above said second diffusion layer, and said first diffusion layer is formed below one of said second transfer electrodes,
• the ratio of said first transfer electrode and said second transfer electrode in width is between 1.6 and 4.0, and
• the charge transfer device is four phase driven,
• wherein the channel potential in the depletion state of said first and second diffusion layers is higher by about half of the driving pulse voltage in said second diffusion layer than the potential of said first diffusion layer.

A charge transfer device comprising:

• a semiconductor substrate of one conductivity type,
• a first diffusion layer of a reverse conductivity type formed on said semiconductor substrate,
• a second diffusion layer of the reverse conductivity type formed in said first diffusion layer,
• a third diffusion layer of the reverse conductivity type formed adjacent to said second diffusion layer and in said first diffusion layer,
• an insulation film formed above said semiconductor substrate, and
• first and second transfer electrodes formed on said insulation film, wherein the length of said first transfer electrode is longer than the length of said second transfer electrode,
• wherein said first transfer electrode is formed at least above both of said second diffusion layer and third diffusion layer, and the impurity concentration of said first diffusion layer is higher than the impurity concentration of said second diffusion layer and said third diffusion layer.