Semiconductor radiation detector

A semiconductor radiation detector device comprising at least one pixel, wherein the at least one pixel comprises a semiconductor substrate and on one surface of the substrate in the following order:

• a first layer of semiconductor of second conductivity type, hereinafter the MIG layer,
• a barrier layer of semiconductor of first conductivity type, configured to form a potential energy barrier for signal charges accumulated in said MIG layer during operation of the device,
• pixel dopings of semiconductor of the second conductivity type, which pixel dopings are adapted to be coupled to at least one pixel voltage in order to create a source and a drain of a pixel-specific transistor;
• wherein the device further comprises a first conductivity type first contact, said. pixel voltage being defined as a potential difference between one of the pixel dopings and the first conductivity type first contact, and a main gate the location of which corresponds at least partly to the location of a channel between said source and said drain,
• wherein:
• the at least one pixel further comprises at least one extra gate next to the main gate and the location of the at least one extra gate corresponds at least partly to the location of a channel between said source and said drain and wherein the at least one extra gate is external to said semiconductor material of the first conductivity type and the second conductivity type,
• comprising in said MIG layer a region the net doping of which is higher than the net doping of the remaining MIG layer around said region, wherein said region is vertically aligned with said main gate,
• comprising a reset gate underneath of which the doping of the MIG layer and barrier layer is weaker than underneath the main gate.

A semiconductor radiation detector device comprising at least one pixel, wherein the at least one pixel comprises a semiconductor substrate (100) and on one surface of the substrate the semiconductor radiation detector comprises:

• a first conductivity type well doping (205),
• a second conductivity type source doping (911, 1111) and a second conductivity type drain doping (912, 1112) inside said first conductivity type well doping (205),
• an opening in the first conductivity type well doping (205) located in between said source doping (911, 1111) and said drain doping (912, 1112),
• a first layer (241) of semiconductor of second conductivity type, hereinafter the MIG layer, said MIG layer located in said opening of the first conductivity type well doping,
• a barrier layer (251) of a semiconductor of first conductivity type arranged directly on the MIG layer in between the MIG layer and said one surface of the substrate and located in said opening of the first conductivity type well doping, said barrier layer configured to form a potential energy barrier for signal charges accumulated in said MIG layer during operation of the semiconductor radiation detector device,
• a main gate (983) external to the semiconductor substrate and located in between said source doping (911, 1111) and said drain doping (912, 1112) as well as above said barrier layer on said opening in the first conductivity type well doping,
• a channel between said source and said drain, wherein part of said channel is located underneath said main gate in said opening in the first conductivity type well doping, said channel carrying charges of said second conductivity type,
• wherein:
• the at least one pixel further comprises at least one extra gate (981, 982) external to the semiconductor substrate and located in between the main gate (983) and the second conductivity type source doping (911, 1111) or drain doping (912, 1112) wherein the at least one extra gate (981, 982) is located above a boundary of said well doping and said opening, and wherein the at least one extra gate (981, 982) is adapted to be coupled to a potential such that the channel resistance is lower beneath the at least one extra gate than beneath the main gate such as to create inside the semiconductor substrate underneath the extra gate:
• an artificial source if the extra gate (981) is located in between the second conductivity type source doping (911, 1111) and the main gate (983), or
• an artificial drain if the extra gate (982) is located in between the second conductivity type drain doping (912, 1112) and the main gate (983).