Radiation detector and associated manufacturing method

A method for producing a radiation detector, comprising:

• a step of producing a stack (Emp) of layers along a direction Z on a substrate (Sub), comprising:
• an absorbent layer (Cabs) configured to absorb the radiation and made from a first semiconductor material (M1) having a first gap (G1) and doping of a first type (t1),
• a first contact layer (Ccont) made from a second material (M2) having a second gap (G2) strictly greater than the first gap (G1),
• a second contact layer (Ccont′) made from a fourth semiconductor material (M4) having a fourth gap (G4) strictly greater than the first gap (G1) and doping of the first type, arranged between the substrate and the absorbent layer,
• an assembly consisting of at least one intermediate layer (Cint, Cinti), referred to as an intermediate assembly (Eint), arranged between the absorbent layer and the first contact layer, each intermediate layer (Cint, Cinti) being made from an intermediate semiconductor material (Mint, Minti) having an intermediate gap (Gint, Ginti) greater than the first gap (G1),
• an upper layer (Csup) arranged on the first contact layer (Ccont) on the opposite side from said intermediate assembly, made from a third semiconductor material (M3) having a third gap (G3) strictly greater than all the other gaps of the stack,
• a passivation layer (Cpass) made from a dielectric material (Mdiel), arranged on the upper layer (Csup),
• the semiconductor layers of the stack being compounds based on elements of groups IIIA and VA of the periodic table of the elements, the second material (M2) comprising the VA element antimony (Sb) and the third material (M3) not comprising the VA element antimony (Sb),
• the second and third materials being configured to have doping of the first type,
• when the first doping type is n, a valence band (BVabs) of the first material (M1) is strictly less than a valence band (BVcont) of the second material (M2) in the detection zones, when the first doping type is p, a conduction band (BCabs) of the first material (M1) is strictly greater than the conduction band (BCcont) of the second material in the detection zones,
• a step of forming openings (Op) in the passivation layer (Cpass),
• a step of incorporating dopant atoms (Ad) into the first contact layer (Ccont) and into the upper layer (Csup) via the openings (Op), so as to form detection zones (Zdet) having a second doping type, the detection zones being separated by separation zones (Zsep) separating one detection zone from another detection zone, each detection zone being surrounded by a separation zone in a plane perpendicular to Z, a detection zone corresponding to a pixel of said detector, the second (M2) and third (M3) materials then having doping of the second type (t2) in the detection zones (Zdet) and doping of the first type (t1) in the separation zones (Zsep),
• when the first doping type is n, the valence band or bands (BVinti) of the intermediate material or materials lying between the valence band (BVabs) of the first material and the valence band (BVcont) of the second material in the detection zones, and being configured to vary monotonically increasingly in the direction from the absorbent layer (Cabs) toward the first contact layer (Ccont),
• when the first doping type is p, the conduction band or bands (BCinti) of the intermediate material or materials (Mint) lying between the conduction band (BCabs) of the first material and the conduction band (BCcont) of the second material in the detection zones, and being configured to vary monotonically decreasingly in the direction from the absorbent layer (Cabs) toward the first contact layer (Ccont),
• a step of metallization through the openings (Op) in order to form a first electrode (E1).