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DE-102008030750-B4 - Radiation detector

DE102008030750B4DE 102008030750 B4DE102008030750 B4DE 102008030750B4DE-102008030750-B4

Abstract

Radiation detector (1) with a semiconductor body (2) comprising an active region (20) for the detection of radiation between a first semiconductor region (21) and a second semiconductor region (22), a lightly doped semiconductor layer (201), a radiation entry surface (10), and a side surface (23) bounding the semiconductor body (2) laterally, wherein the active region (20) is formed in the lightly doped semiconductor layer (201), and a passive region (6) is formed at least partially along the side surface (23) by means of a recess (25) in the semiconductor body (2), which at least partially prevents radiation incident laterally in the direction of the active region (20) from contributing to the generation of a signal of the radiation detector (1) in the active region (20), wherein the recess (25) is filled with a filler material that absorbs or reflects the incident radiation, and wherein the recess (25) extends through the lightly doped extending through the semiconductor layer (201) and limiting the active region (20) in a lateral direction, wherein the recess (25) is formed between the active region (20) and the side surface (23) of the semiconductor body (2), the side surface (23) extending from the radiation entry surface (10) to a rear side of the semiconductor body (2) facing away from the radiation entry surface (10).

Inventors

  • Christian, Dr. Müller
  • Werner, Dr. Kuhlmann

Assignees

  • OSRAM Opto Semiconductors Gesellschaft mit beschränkter Haftung

Dates

Publication Date
20260513
Application Date
20080627

Claims (13)

  1. Radiation detector (1) with a semiconductor body (2) comprising an active region (20) for the detection of radiation between a first semiconductor region (21) and a second semiconductor region (22), a lightly doped semiconductor layer (201), a radiation entry surface (10), and a side surface (23) bounding the semiconductor body (2) laterally, wherein the active region (20) is formed in the lightly doped semiconductor layer (201), and a passive region (6) is formed at least partially along the side surface (23) by means of a recess (25) in the semiconductor body (2), which at least partially prevents radiation incident laterally in the direction of the active region (20) from contributing to the generation of a signal of the radiation detector (1) in the active region (20), wherein the recess (25) is filled with a filler material that absorbs or reflects the incident radiation, and wherein the recess (25) extends through the lightly doped extending through the semiconductor layer (201) and limiting the active region (20) in a lateral direction, wherein the recess (25) is formed between the active region (20) and the side surface (23) of the semiconductor body (2), the side surface (23) extending from the radiation entry surface (10) to a rear side of the semiconductor body (2) facing away from the radiation entry surface (10).
  2. Radiation detector according to Claim 1 , in which the passive area (6) surrounds the active area (20) laterally.
  3. Radiation detector according to one of the preceding claims, in which a filter structure (4) is formed on the radiation entry surface (10) of the semiconductor body (2).
  4. Radiation detector according to one of the preceding claims, wherein the active area (20) is limited in a vertical direction on the side facing away from the radiation entry surface (10) of the semiconductor body (2) by means of an insulating layer (261).
  5. Radiation detector according to one of the Claims 1 until 4 , in which the semiconductor body (2) has a cavity (29) that limits the active area (20) on the side facing away from the radiation entry surface (10).
  6. Radiation detector according to one of the Claims 1 until 3 , in which the active region (20) is formed by means of a semiconductor layer having a thickness between 1 µm and 8 µm including the radiation entry side and is adjacent to a heavily doped semiconductor layer with a doping concentration of at least 1 · 10 18 cm -3 on the side facing away from the radiation entry side (10).
  7. radiation detector according to one of the preceding Claims 1 until 6 , in which a further diode structure (8) is formed on the side of the active region (20) facing away from the radiation entry side (10).
  8. Radiation detector according to Claim 7 , in which the further diode structure (8) is short-circuited.
  9. Radiation detector according to one of the preceding claims, wherein the active area (20) contains silicon.
  10. Radiation detector according to one of the preceding claims, wherein the active region (20) is formed according to a photodiode, a phototransistor or a photo-Darlington circuit.
  11. Radiation detector according to one of the preceding claims, which is designed such that a spectral sensitivity distribution of the radiation detector (1) is adapted to that of the human eye.
  12. Radiation detector according to one of the preceding claims, wherein the filling material contains polycrystalline silicon.
  13. Radiation detector according to one of the preceding claims, wherein the recess extends in a vertical direction from the Radiation entry surface (10) extends at least to the active area (20).

Description

The present application relates to a radiation detector. Typical silicon photodiodes exhibit a relatively broadband spectral sensitivity from approximately 200 nm to 1150 nm, with the spectral sensitivity maximum in the near-infrared at wavelengths between 750 nm and 900 nm. Particularly due to this high sensitivity in the near-infrared, the spectral sensitivity distribution of these diodes shows strong deviations from the sensitivity of the human eye, which has a maximum at approximately 550 nm. A conventional radiation detector is made from the printed material DE 36 17 229 A1 known. Further radiation detectors are from the printed materials. JP 2003 - 158 291 A1 and US 2005 / 0 184 353 A1 known. The task is to specify a radiation detector whose spectral sensitivity distribution is adapted to a given sensitivity distribution, in particular to the sensitivity distribution of the human eye. This problem is solved by a radiation detector according to claim 1. Further embodiments and developments are the subject of the dependent claims. According to one embodiment, a radiation detector comprises a semiconductor body having an active region for the detection of radiation between a first semiconductor region and a second semiconductor region, a lightly doped semiconductor layer, a radiation entry surface, and a side surface bounding the semiconductor body laterally. Along the side surface, a passive region is formed, at least partially, by means of a recess in the semiconductor body. This passive region at least partially prevents radiation incident laterally towards the active region from contributing to the generation of a signal in the active region of the radiation detector. The active region is formed within the lightly doped semiconductor layer. The cavity is filled with a filler material that absorbs or reflects the incident radiation. Furthermore, the cavity extends through the lightly doped semiconductor layer and laterally defines the active region. Additionally, the cavity is located between the active region and the side face of the semiconductor body. This side face extends from the radiation entry surface to the rear face of the semiconductor body opposite the radiation entry surface. The passive section allows the portion of radiation entering the active section from the side to contribute to the signal, for example by generating and spatially separating electron-hole pairs. This radiation, incident laterally towards the active section, could amplify the signal component within the active section, potentially resulting in a sensitivity distribution of the radiation detector that deviates from a predetermined one. In other words, the signal component of the radiation detector is maximized for the radiation coupled into the active section through the radiation entrance area. The spectral sensitivity distribution of the radiation detector can thus be simplified to fit a given sensitivity distribution, preferably the sensitivity distribution of the human eye. An active region is understood to be, in particular, a region where the absorption of radiation leads to a signal that can be detected externally by the radiation detector. Signal generation can occur, for example, through the creation of electron-hole pairs as a result of radiation absorption, whereby the electrons and holes are separated from each other, perhaps in a space charge region, thus leading to an externally detectable signal. In contrast, a passive region is understood to be a region where the incident radiation contributes no, or at least no significant, part to the signal of the radiation detector. For example, the passive region can be designed such that the radiation is absorbed and/or reflected within it. Unlike the active region, the passive region is advantageously designed such that absorption of radiation within it results in no, or at least no significant, externally detectable signal. In a preferred embodiment, the passive region extends between the active region and the side face of the semiconductor body. This reduces the proportion of radiation that enters the semiconductor body laterally and contributes to signal generation in the active region. The coupling of the radiation that causes signal generation in the active region thus occurs essentially... chen via the radiation entry surface of the semiconductor body. In particular, the radiation can be blocked by means of the passive section; that is, it can at least partially prevent laterally incident radiation from reaching the active section. This radiation can therefore be blocked before it can contribute to a signal component in the active section that could cause a sensitivity distribution that deviates from the specified sensitivity distribution. In a preferred further development, the passive region surrounds the active region laterally in a top-down view of the semiconductor body. In particular, the passive region can completely surround the active region latera