WO2022118673A1 - Sensor element and electronic device - Google Patents

Sensor element and electronic device Download PDF

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Publication number
WO2022118673A1
WO2022118673A1 PCT/JP2021/042533 JP2021042533W WO2022118673A1 WO 2022118673 A1 WO2022118673 A1 WO 2022118673A1 JP 2021042533 W JP2021042533 W JP 2021042533W WO 2022118673 A1 WO2022118673 A1 WO 2022118673A1
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Prior art keywords
sensor element
transfer
semiconductor substrate
transfer unit
unit
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PCT/JP2021/042533
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French (fr)
Japanese (ja)
Inventor
武 山崎
悠介 大竹
拓郎 村瀬
英樹 荒井
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ソニーセミコンダクタソリューションズ株式会社
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Publication of WO2022118673A1 publication Critical patent/WO2022118673A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures

Definitions

  • the present disclosure relates to sensor elements and electronic devices, and more particularly to sensor elements and electronic devices capable of further improving measurement accuracy.
  • TOF Time Of Flight
  • iTOF Time Of Flight
  • iTOF which indirectly measures distance using pulsed light with a rectangular wavelength, has a structure in which two gates are arranged in one pixel cell, and electrons generated by photoelectric conversion in a photodiode turn on the gate. It is distributed to each tap according to the timing of / off.
  • Patent Document 1 is provided with two gates on the surface of a semiconductor substrate for transferring electrons obtained by photoelectrically converting light incident from the back surface of the semiconductor substrate with a pn junction photodiode on the surface of the semiconductor substrate, and a plurality of gates synchronized with the modulation cycle of the irradiation light are provided.
  • a distance imaging device having a configuration in which a charge is read from a photodiode at a timing is disclosed. In such a configuration, the electrons that have been photoelectrically converted from the light incident on the semiconductor substrate move from the deep part by diffusion current, and after having a potential gradient toward the surface of the semiconductor substrate, they move near the gate due to drift. It flows in the direction in which the gate is turned on and is read out.
  • This disclosure is made in view of such a situation, and makes it possible to further improve the measurement accuracy.
  • the sensor element on one side of the present disclosure includes a photoelectric conversion unit that photoelectrically converts light emitted from the back surface side of the semiconductor substrate, and a charge generated by the photoelectric conversion unit provided on the front surface side of the semiconductor substrate.
  • the electronic device on one side of the present disclosure includes a photoelectric conversion unit that photoelectrically converts light emitted from the back surface side of the semiconductor substrate, and a charge generated by the photoelectric conversion unit provided on the front surface side of the semiconductor substrate.
  • the light emitted from the back surface side of the semiconductor substrate is photoelectrically converted in the photoelectric conversion unit, and the first transfer unit and the second transfer unit that transfer the charges generated in the photoelectric conversion unit are semiconductors.
  • the structure is provided on the surface side of the substrate and has a predetermined depth from the surface of the semiconductor substrate, and the structural portion is arranged between the first transfer portion and the second transfer portion.
  • FIG. 1 is a diagram showing a configuration example of a first embodiment of a sensor element to which the present technique is applied.
  • FIG. 1 shows an example of a cross-sectional configuration of pixels 13 arranged in an array on a semiconductor substrate 12 constituting a sensor element 11.
  • the sensor element 11 is a back-illuminated type in which light is radiated from the back surface of the semiconductor substrate 12 (the surface facing the lower side of FIG. 1) to the pixels 13.
  • the sensor element 11 is provided with an on-chip microlens 14 that collects light for each pixel 13 so as to be laminated on the back surface side of the semiconductor substrate 12.
  • the sensor element 11 is provided with a light-shielding portion 15 that blocks light in order to prevent contamination from other adjacent pixels 13 so as to be dug from the back surface side of the semiconductor substrate 12.
  • the pixel 13 includes a photoelectric conversion unit 21, transfer transistors 22-1 and 22-2, and a structure 23.
  • the photoelectric conversion unit 21 photoelectrically converts the light incident on the pixel 13 and generates an electric charge according to the amount of the light. Further, the photoelectric conversion unit 21 has a configuration in which the potential gradient is adjusted according to the concentration of impurities ion-implanted into the semiconductor substrate 12. For example, the photoelectric conversion unit 21 is configured such that the potential decreases from the back surface side to the front surface side of the semiconductor substrate 12, and the potential decreases inside the pixel 13 rather than outside. As a result, the electric charge generated in the photoelectric conversion unit 21 tends to flow toward the center of the surface side of the semiconductor substrate 12.
  • the transfer transistors 22-1 and 22-2 transfer the electric charge generated in the photoelectric conversion unit 21 to the outside of the photoelectric conversion unit 21 (for example, a floating diffusion unit (not shown)). For example, when the gate voltage Gate1 is applied and the transfer transistor 22-1 is turned on, the electric charge generated in the photoelectric conversion unit 21 is transferred via the transfer transistor 22-1. Further, when the gate voltage Gate 2 is applied and the transfer transistor 22-2 is turned on, the electric charge generated in the photoelectric conversion unit 21 is transferred via the transfer transistor 22-2.
  • the structure 23 is provided in the photoelectric conversion unit 21 with a structure having a predetermined depth from the surface of the semiconductor substrate 12, and is arranged at a position intermediate between the transfer transistors 22-1 and 22-2.
  • the structure 23 has a structure in which an oxide is embedded in a trench formed by shallowly carving the surface of the semiconductor substrate 12.
  • the depth of the structure 23 is preferably set to a range affected by the respective potentials when the transfer transistors 22-1 and 22-2 are turned on, specifically, in the range of 80 to 100 nm. Set in.
  • the pixels 13 are configured in this way, and the flow of electric charges generated by the photoelectric conversion in the photoelectric conversion unit 21 is from the back surface side to the front surface side of the semiconductor substrate 12 as shown by the white arrows shown in FIG.
  • the structure 23 branches into a direction toward the transfer transistor 22-1 side and a direction toward the transfer transistor 22-2 side. Therefore, the pixel 13 is configured to be provided with the structure 23 so that the electric charge generated by the photoelectric conversion unit 21 surely flows in the intended directions of the transfer transistors 22-1 and 22-2, respectively. It can be configured.
  • the pixel 13 is configured such that when the transfer transistor 22-1 is turned on, the charge easily flows toward the transfer transistor 22-1, and the charge is suppressed from flowing toward the transfer transistor 22-2. It has become. Similarly, when the transfer transistor 22-2 is turned on, the pixel 13 facilitates the flow of electric charges toward the transfer transistor 22-2 and suppresses the electric charges toward the transfer transistor 22-1. It is composed.
  • FIG. 2 shows an example of a flat layout of the pixels 13 when the semiconductor substrate 12 is viewed from the surface side.
  • the structure 23 is arranged in a region where the electric field is concentrated in the vicinity of the transfer transistors 22-1 and 22-2, and the transfer transistors 22-1 and 22-2 are arranged on the surface side of the semiconductor substrate 12. It is provided so as to divide the space. Further, the structure 23 may be arranged so that a charge flow is generated more as intended according to the potential state of the photoelectric conversion unit 21.
  • the pixel 13 is provided with an overflow gate 24 for discharging the electric charge accumulated in the photoelectric conversion unit 21, and the arrangement of the structure 23 is set at a position separated from the overflow gate 24 by a predetermined interval. The charge.
  • the pixel 13 can prevent the structure 23 from hindering the discharge when the charge is discharged from the overflow gate 24. That is, in the structure in which the structure 23 is arranged in the vicinity of the overflow gate 24, it is assumed that it becomes difficult to discharge the electric charge from the overflow gate 24, and the pixel 13 does not have such a structure.
  • the sensor element 11 configured as described above has a structure in which the structure 23 is provided, so that it is possible to prevent the electric charge from moving to the opposite side with respect to the intended direction. As a result, the sensor element 11 can increase the Cmod and significantly improve the PDNU. Therefore, the sensor element 11 can suppress the occurrence of an error in the measurement result, and as a result, the measurement accuracy can be further improved.
  • the sensor element 11 infrared light that reaches deep into the semiconductor substrate 12 is reflected by the structure 23 provided on the surface side of the semiconductor substrate 12, and the reflected light is also photoelectrically converted by the photoelectric conversion unit 21. As a result, the sensor element 11 can obtain the effect of improving the quantum efficiency Qe.
  • the sensor element 11 When performing pupil correction in the sensor element 11, it is only necessary to adjust the position of the on-chip microlens 14 according to the position of the pixel 13. That is, the sensor element 11 can cope with the pupil correction without changing the arrangement of the structure 23.
  • FIG. 3 is a diagram showing a configuration example of a second embodiment of the sensor element to which the present technique is applied.
  • the same reference numerals are given to the configurations common to the sensor element 11 of FIG. 1, and detailed description thereof will be omitted.
  • the planar layout of the pixel 13A is the same as the layout shown in FIG.
  • the sensor element 11A has a configuration different from that of the sensor element 11 of FIG. 1 in that the shape of the structure 23A provided in the pixel 13A is different from the shape of the structure 23 of FIG. It has a common structure in other respects.
  • the structure 23 in FIG. 1 has a rectangular cross-sectional shape
  • the structure 23A has a flow direction in which charges are directed from the center of the pixel 13A to the transfer transistors 22-1 and 22-2, respectively. It has an inverted triangular cross-sectional shape with a tapered surface that slopes along it. That is, the structure 23A has a structure in which an oxide is embedded in a trench formed so that when the semiconductor substrate 12 is dug from the surface side, the digging depth becomes deeper and the digging width becomes narrower. It has become.
  • the sensor element 11A has a structure in which the structure 23A having a tapered surface is provided in the sensor element 11A, so that the electric charge can be more easily directed to each of the transfer transistors 22-1 and 22-2. Can be. That is, when the transfer transistor 22-1 is turned on, the charge is more likely to flow toward the transfer transistor 22-1, and when the transfer transistor 22-2 is turned on, the charge is more toward the transfer transistor 22-2. Charges flow easily. As a result, the sensor element 11B can be expected to generate a charge flow as intended as compared with the sensor element 11 in FIG. 1, and the measurement accuracy can be further improved.
  • the sensor element 11A has an increased reflection area of infrared light by the structure 23A as compared with the structure 23 in FIG. 1, further improvement in quantum efficiency Qe can be expected.
  • FIG. 4 is a diagram showing a configuration example of a third embodiment of the sensor element to which the present technique is applied.
  • the same reference numerals are given to the configurations common to the sensor element 11 of FIG. 1, and detailed description thereof will be omitted.
  • the shapes of the transfer transistors 22B-1 and 22B-2 and the structure 23B provided in the pixel 13B are the same as those of the transfer transistors 22-1 and 22-2 and the structure 23 in FIG. It has a different configuration from the sensor element 11 in FIG. 1 in that it differs from the shape of the above, and has a configuration common to other points. Further, the planar layout of the pixel 13B is the same as the layout shown in FIG.
  • the transfer transistors 22-1 and 22-2 of FIG. 1 are formed so that the gate electrodes are laminated on the surface of the semiconductor substrate 12, whereas the transfer transistors 22B-1 and 22B-2 are semiconductors. It is formed so that the gate electrode is arranged by digging the surface of the substrate 12. Further, the structure 23B is formed deeper than the structure 23 of FIG. 1 by the amount that the transfer transistors 22B-1 and 22B-2 are embedded and formed to a predetermined depth of the semiconductor substrate 12. There is.
  • the structure 23B has a shape 0.3 ⁇ m deeper than the structure 23 of FIG.
  • the transfer transistors 22B-1 and 22B-2 are turned on by the transfer transistors 22B-1 and 22B-2 having the gate electrodes embedded from the surface of the semiconductor substrate 12 in the sensor element 11B.
  • the range affected by the potential can be deepened.
  • the sensor element 11B can obtain the effect of generating a charge flow as intended when the transfer transistors 22B-1 and 22B-2 are turned on, respectively, and further improve the measurement accuracy. be able to.
  • the effect of improving the quantum efficiency Qe can be obtained by providing the structure 23B as in the sensor element 11 of FIG.
  • FIG. 5 is a diagram showing a configuration example of a fourth embodiment of the sensor element to which the present technique is applied.
  • the same reference numerals are given to the configurations common to the sensor element 11 in FIG. 1, and detailed description thereof will be omitted.
  • the shapes of the transfer transistors 22C-1 and 22C-2 provided in the pixel 13C are different from the shapes of the transfer transistors 22-1 and 22-2 in FIG. Further, the sensor element 11C has a configuration different from that of the sensor element 11 of FIG. 1 in that the structure 23 is not provided, and has a configuration common to other points.
  • the transfer transistors 22C-1 and 22C-2 are formed so that the gate electrodes are arranged by digging the surface of the semiconductor substrate 12, similarly to the transfer transistors 22B-1 and 22B-2 of FIG.
  • the sensor element 11C like the sensor element 11B, can deepen the range affected by the potential when the transfer transistors 22C-1 and 22C-2 are turned on.
  • the sensor element 11C can improve the measurement accuracy.
  • the sensor element 11 as described above can be applied to an electronic device such as a measuring device that measures a distance using a TOF and acquires a distance measurement image.
  • FIG. 6 is a block diagram showing a configuration example of an image pickup device mounted on an electronic device.
  • the image pickup device 101 includes an optical system 102, an image pickup element 103, a signal processing circuit 104, a monitor 105, and a memory 106, and can capture still images and moving images.
  • the optical system 102 is configured to have one or a plurality of lenses, and guides the image light (incident light) from the subject to the image pickup element 103 to form an image on the light receiving surface (sensor unit) of the image pickup element 103.
  • the sensor element 11 described above is applied as the image pickup element 103. Electrons are accumulated in the image pickup device 103 for a certain period of time according to the image formed on the light receiving surface via the optical system 102. Then, a signal corresponding to the electrons stored in the image pickup device 103 (for example, the electric charge distributed to each of the transfer transistors 22-1 and 22-2) is supplied to the signal processing circuit 104.
  • the signal processing circuit 104 performs various signal processing on the pixel signal output from the image pickup device 103.
  • the ranging image (image data) obtained by performing signal processing by the signal processing circuit 104 is supplied to the monitor 105 and displayed, or supplied to the memory 106 and stored (recorded).
  • the image pickup apparatus 101 configured in this way, by applying the sensor element 11 described above, for example, a more accurate ranging image can be captured.
  • the present technology can also have the following configurations.
  • a photoelectric conversion unit that photoelectrically converts the light emitted from the back surface side of the semiconductor substrate, and A first transfer unit and a second transfer unit, which are provided on the surface side of the semiconductor substrate and transfer electric charges generated by the photoelectric conversion unit,
  • a sensor element having a structure having a predetermined depth from the surface of the semiconductor substrate and including a structural portion arranged between the first transfer unit and the second transfer unit.
  • the depth of the structural unit is the potential of each of the first transfer unit or the second transfer unit when the charge transfer by the first transfer unit or the second transfer unit is turned on.
  • the sensor element according to (1) above which is set within the range of influence.
  • the structural unit is provided at a position that divides between the first transfer unit and the second transfer unit in a plan view, and is a discharge unit that discharges the electric charge accumulated in the photoelectric conversion unit.
  • an on-chip microlens laminated on the back surface side of the semiconductor substrate and condensing light for each pixel having the photoelectric conversion unit is further provided.
  • the structural portion has a cross-sectional shape having a tapered surface inclined along the direction of charge flow toward each of the first transfer portion and the second transfer portion. Any of the above (1) to (5).
  • (7) The above (1) to (6), wherein each of the first transfer unit and the second transfer unit is configured to have a gate electrode embedded and provided from the surface of the semiconductor substrate. Sensor element.
  • a photoelectric conversion unit that photoelectrically converts the light emitted from the back surface side of the semiconductor substrate, and A first transfer unit and a second transfer unit, which are provided on the surface side of the semiconductor substrate and transfer electric charges generated by the photoelectric conversion unit,
  • An electronic device having a structure having a predetermined depth from the surface of the semiconductor substrate and having a sensor element having a structure portion arranged between the first transfer unit and the second transfer unit.

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Abstract

The present disclosure relates to a sensor element and an electronic device that enable enhanced measurement accuracy. A sensor element according to the present invention has, on a front surface side of a photoelectric conversion unit for performing photoelectric conversion of light radiated from a back surface side of a semiconductor substrate, a first transfer unit and a second transfer unit for transferring electric charge generated in the photoelectric conversion unit, is structured at a prescribed depth from a front surface of the semiconductor substrate, and is configured so that a structure is arranged between the first transfer unit and the second transfer unit. This technology is applicable to, for example, a measuring device for performing distance measurement by using a TOF method.

Description

センサ素子および電子機器Sensor elements and electronic devices
　本開示は、センサ素子および電子機器に関し、特に、より測定精度の向上を図ることができるようにしたセンサ素子および電子機器に関する。 The present disclosure relates to sensor elements and electronic devices, and more particularly to sensor elements and electronic devices capable of further improving measurement accuracy.
　従来、対象物までの距離を測定する測距センサでは、光が対象物に反射して返ってくるまでの時間を計測するTOF（Time Of Flight）が利用されている。例えば、矩形波長のパルス光を利用して間接的に距離を測定するiTOFでは、１つの画素セルの中に２つのゲートを並べた構造で、フォトダイオードにおける光電変換により発生した電子がゲートのオン／オフのタイミングに合わせて、それぞれのタップに振り分けられる。 Conventionally, in the distance measuring sensor that measures the distance to the object, TOF (Time Of Flight) that measures the time until the light is reflected by the object and returned is used. For example, iTOF, which indirectly measures distance using pulsed light with a rectangular wavelength, has a structure in which two gates are arranged in one pixel cell, and electrons generated by photoelectric conversion in a photodiode turn on the gate. It is distributed to each tap according to the timing of / off.
　このとき、それらのタップの間にある電子が、オンとなった側のゲートの方に全て入らずに、オフとなった側のゲートに入ってしまうことがある。その場合、それぞれのタップで電荷を分離する電荷分離効率（Cmod：Contrast between active and inactive tap）が低下することになり、測定結果である距離に誤差が発生することになってしまう。また、フォトダイオードの不均一性（PDNU：Photodiode Non Uniformity）も課題となる。 At this time, all the electrons between those taps may not enter the gate on the turned side but enter the gate on the turned side. In that case, the charge separation efficiency (Cmod: Contrast between active and inactive tap) that separates the charge with each tap is lowered, and an error occurs in the distance that is the measurement result. In addition, the non-uniformity of photodiodes (PDNU: Photodiode Non Uniformity) is also an issue.
　例えば、特許文献１には、半導体基板の裏面から入射する光をｐｎ接合フォトダイオードで光電変換した電子を転送する２つのゲートを半導体基板の表面に備え、照射光の変調周期に同期した複数のタイミングでフォトダイオードから電荷を読み出す構成の距離画像装置が開示されている。このような構成では、半導体基板に入射した光が光電変換された電子は、深部から拡散電流で移動し、半導体基板の表面に向かって電位勾配があることよりドリフトによってゲート近くに移動した後、ゲートがオンになっている方向に流れて読み出される。 For example, Patent Document 1 is provided with two gates on the surface of a semiconductor substrate for transferring electrons obtained by photoelectrically converting light incident from the back surface of the semiconductor substrate with a pn junction photodiode on the surface of the semiconductor substrate, and a plurality of gates synchronized with the modulation cycle of the irradiation light are provided. A distance imaging device having a configuration in which a charge is read from a photodiode at a timing is disclosed. In such a configuration, the electrons that have been photoelectrically converted from the light incident on the semiconductor substrate move from the deep part by diffusion current, and after having a potential gradient toward the surface of the semiconductor substrate, they move near the gate due to drift. It flows in the direction in which the gate is turned on and is read out.
特開２００９－８５３７号公報Japanese Unexamined Patent Publication No. 2009-8537
　上述したように、ゲートのオン／オフで電荷の振り分けを行う構成において、意図した方向と反対側に電荷が移動してしまう場合には測定結果に誤差が発生することになる結果、測定精度が低下することになっていた。 As described above, in the configuration in which the charge is distributed by turning the gate on / off, if the charge moves in the direction opposite to the intended direction, an error will occur in the measurement result, and as a result, the measurement accuracy will be improved. It was supposed to drop.
　本開示は、このような状況に鑑みてなされたものであり、より測定精度の向上を図ることができるようにするものである。 This disclosure is made in view of such a situation, and makes it possible to further improve the measurement accuracy.
　本開示の一側面のセンサ素子は、半導体基板の裏面側から照射された光を光電変換する光電変換部と、前記半導体基板の表面側に設けられ、前記光電変換部で発生した電荷を転送する第１の転送部および第２の転送部と、前記半導体基板の表面から所定の深さとなる構造で、前記第１の転送部および前記第２の転送部の間に配置される構造部とを備える。 The sensor element on one side of the present disclosure includes a photoelectric conversion unit that photoelectrically converts light emitted from the back surface side of the semiconductor substrate, and a charge generated by the photoelectric conversion unit provided on the front surface side of the semiconductor substrate. A first transfer unit and a second transfer unit, and a structure unit having a structure having a predetermined depth from the surface of the semiconductor substrate and arranged between the first transfer unit and the second transfer unit. Be prepared.
　本開示の一側面の電子機器は、半導体基板の裏面側から照射された光を光電変換する光電変換部と、前記半導体基板の表面側に設けられ、前記光電変換部で発生した電荷を転送する第１の転送部および第２の転送部と、前記半導体基板の表面から所定の深さとなる構造で、前記第１の転送部および前記第２の転送部の間に配置される構造部とを有するセンサ素子を備える。 The electronic device on one side of the present disclosure includes a photoelectric conversion unit that photoelectrically converts light emitted from the back surface side of the semiconductor substrate, and a charge generated by the photoelectric conversion unit provided on the front surface side of the semiconductor substrate. A first transfer unit and a second transfer unit, and a structure unit having a structure having a predetermined depth from the surface of the semiconductor substrate and arranged between the first transfer unit and the second transfer unit. It is equipped with a sensor element to have.
　本開示の一側面においては、半導体基板の裏面側から照射された光が光電変換部において光電変換され、光電変換部で発生した電荷を転送する第１の転送部および第２の転送部が半導体基板の表面側に設けられ、半導体基板の表面から所定の深さとなる構造で、第１の転送部および第２の転送部の間に構造部が配置される。 In one aspect of the present disclosure, the light emitted from the back surface side of the semiconductor substrate is photoelectrically converted in the photoelectric conversion unit, and the first transfer unit and the second transfer unit that transfer the charges generated in the photoelectric conversion unit are semiconductors. The structure is provided on the surface side of the substrate and has a predetermined depth from the surface of the semiconductor substrate, and the structural portion is arranged between the first transfer portion and the second transfer portion.
本技術を適用したセンサ素子の第１の実施の形態の構成例を示す図である。It is a figure which shows the structural example of the 1st Embodiment of the sensor element which applied this technique. センサ素子の平面レイアウトの一例を示す図である。It is a figure which shows an example of the plane layout of a sensor element. 本技術を適用したセンサ素子の第２の実施の形態の構成例を示す図である。It is a figure which shows the structural example of the 2nd Embodiment of the sensor element which applied this technique. 本技術を適用したセンサ素子の第３の実施の形態の構成例を示す図である。It is a figure which shows the structural example of the 3rd Embodiment of the sensor element which applied this technique. 本技術を適用したセンサ素子の第４の実施の形態の構成例を示す図である。It is a figure which shows the structural example of the 4th Embodiment of the sensor element which applied this technique. 電子機器の構成例を示すブロック図である。It is a block diagram which shows the structural example of an electronic device.
　以下、本技術を適用した具体的な実施の形態について、図面を参照しながら詳細に説明する。 Hereinafter, specific embodiments to which this technique is applied will be described in detail with reference to the drawings.
　＜センサ素子の第１の構成例＞
　図１は、本技術を適用したセンサ素子の第１の実施の形態の構成例を示す図である。 <First configuration example of the sensor element>
FIG. 1 is a diagram showing a configuration example of a first embodiment of a sensor element to which the present technique is applied.
　図１には、センサ素子１１を構成する半導体基板１２にアレイ状に配置される画素１３の断面構成の一例が示されている。センサ素子１１は、半導体基板１２の裏面（図１の下側を向く面）から画素１３に光が照射される裏面照射型となっている。 FIG. 1 shows an example of a cross-sectional configuration of pixels 13 arranged in an array on a semiconductor substrate 12 constituting a sensor element 11. The sensor element 11 is a back-illuminated type in which light is radiated from the back surface of the semiconductor substrate 12 (the surface facing the lower side of FIG. 1) to the pixels 13.
　センサ素子１１には、半導体基板１２の裏面側に積層するように、画素１３ごとに光を集光するオンチップマイクロレンズ１４が設けられる。センサ素子１１には、半導体基板１２の裏面側から掘り込むように、隣接する他の画素１３からの混入を防止するために光を遮光する遮光部１５が設けられる。 The sensor element 11 is provided with an on-chip microlens 14 that collects light for each pixel 13 so as to be laminated on the back surface side of the semiconductor substrate 12. The sensor element 11 is provided with a light-shielding portion 15 that blocks light in order to prevent contamination from other adjacent pixels 13 so as to be dug from the back surface side of the semiconductor substrate 12.
　画素１３は、光電変換部２１、転送トランジスタ２２－１および２２－２、並びに、構造物２３を備えて構成される。 The pixel 13 includes a photoelectric conversion unit 21, transfer transistors 22-1 and 22-2, and a structure 23.
　光電変換部２１は、画素１３に入射した光を光電変換し、その光の光量に応じた電荷を発生する。また、光電変換部２１は、半導体基板１２にイオン注入される不純物の濃度によってポテンシャルの勾配が調整された構成となっている。例えば、光電変換部２１は、半導体基板１２の裏面側から表面側に向かうに従ってポテンシャルが低くなり、かつ、画素１３の外側よりも内側においてポテンシャルが低くなるように構成される。これにより、光電変換部２１において発生した電荷が半導体基板１２の表面側の中央に向かって流れ易くなる。 The photoelectric conversion unit 21 photoelectrically converts the light incident on the pixel 13 and generates an electric charge according to the amount of the light. Further, the photoelectric conversion unit 21 has a configuration in which the potential gradient is adjusted according to the concentration of impurities ion-implanted into the semiconductor substrate 12. For example, the photoelectric conversion unit 21 is configured such that the potential decreases from the back surface side to the front surface side of the semiconductor substrate 12, and the potential decreases inside the pixel 13 rather than outside. As a result, the electric charge generated in the photoelectric conversion unit 21 tends to flow toward the center of the surface side of the semiconductor substrate 12.
　転送トランジスタ２２－１および２２－２は、光電変換部２１において発生した電荷を、光電変換部２１の外部（例えば、図示しないフローティングディフュージョン部）に転送する。例えば、ゲート電圧Gate1が印加されて転送トランジスタ２２－１がオンになると、光電変換部２１において発生した電荷は、転送トランジスタ２２－１を介して転送される。また、ゲート電圧Gate2が印加されて転送トランジスタ２２－２がオンになると、光電変換部２１において発生した電荷は、転送トランジスタ２２－２を介して転送される。 The transfer transistors 22-1 and 22-2 transfer the electric charge generated in the photoelectric conversion unit 21 to the outside of the photoelectric conversion unit 21 (for example, a floating diffusion unit (not shown)). For example, when the gate voltage Gate1 is applied and the transfer transistor 22-1 is turned on, the electric charge generated in the photoelectric conversion unit 21 is transferred via the transfer transistor 22-1. Further, when the gate voltage Gate 2 is applied and the transfer transistor 22-2 is turned on, the electric charge generated in the photoelectric conversion unit 21 is transferred via the transfer transistor 22-2.
　構造物２３は、半導体基板１２の表面から所定の深さとなる構造で光電変換部２１内に設けられ、転送トランジスタ２２－１および２２－２の中間となる位置に配置される。例えば、構造物２３は、半導体基板１２の表面を浅く彫り込んで形成されるトレンチに、酸化物が埋め込まれた構成となっている。構造物２３の深さは、転送トランジスタ２２－１および２２－２がオンとなったときに、それぞれのポテンシャルの影響が及ぶ範囲に設定することが好ましく、具体的には、８０～１００ｎｍの範囲内に設定される。 The structure 23 is provided in the photoelectric conversion unit 21 with a structure having a predetermined depth from the surface of the semiconductor substrate 12, and is arranged at a position intermediate between the transfer transistors 22-1 and 22-2. For example, the structure 23 has a structure in which an oxide is embedded in a trench formed by shallowly carving the surface of the semiconductor substrate 12. The depth of the structure 23 is preferably set to a range affected by the respective potentials when the transfer transistors 22-1 and 22-2 are turned on, specifically, in the range of 80 to 100 nm. Set in.
　このように画素１３は構成されており、光電変換部２１における光電変換で発生した電荷の流れは、図１に示す白抜きの矢印で表されるように、半導体基板１２の裏面側から表面側に向かった後、構造物２３によって転送トランジスタ２２－１側に向かう方向と転送トランジスタ２２－２側に向かう方向とに分岐される。従って、画素１３は、構造物２３を設けた構成とすることによって、光電変換部２１で発生した電荷が、確実に、転送トランジスタ２２－１および２２－２それぞれ意図した方向に向かって流れるような構成とすることができる。 The pixels 13 are configured in this way, and the flow of electric charges generated by the photoelectric conversion in the photoelectric conversion unit 21 is from the back surface side to the front surface side of the semiconductor substrate 12 as shown by the white arrows shown in FIG. After heading toward, the structure 23 branches into a direction toward the transfer transistor 22-1 side and a direction toward the transfer transistor 22-2 side. Therefore, the pixel 13 is configured to be provided with the structure 23 so that the electric charge generated by the photoelectric conversion unit 21 surely flows in the intended directions of the transfer transistors 22-1 and 22-2, respectively. It can be configured.
　つまり、画素１３は、転送トランジスタ２２－１がオンとなったときには、転送トランジスタ２２－１に向かって電荷が流れ易くなるとともに、転送トランジスタ２２－２に電荷が向かうのが抑制されるような構成となっている。同様に、画素１３は、転送トランジスタ２２－２がオンとなったときには、転送トランジスタ２２－２に向かって電荷が流れ易くなるとともに、転送トランジスタ２２－１に電荷が向かうのが抑制されるような構成となっている。 That is, the pixel 13 is configured such that when the transfer transistor 22-1 is turned on, the charge easily flows toward the transfer transistor 22-1, and the charge is suppressed from flowing toward the transfer transistor 22-2. It has become. Similarly, when the transfer transistor 22-2 is turned on, the pixel 13 facilitates the flow of electric charges toward the transfer transistor 22-2 and suppresses the electric charges toward the transfer transistor 22-1. It is composed.
　図２には、半導体基板１２を表面側から見た画素１３の平面的なレイアウトの一例が示されている。 FIG. 2 shows an example of a flat layout of the pixels 13 when the semiconductor substrate 12 is viewed from the surface side.
　図２に示すように、構造物２３は、転送トランジスタ２２－１および２２－２の近傍で電界が集中する領域に配置され、半導体基板１２の表面側において転送トランジスタ２２－１および２２－２の間を分断するように設けられる。また、構造物２３は、光電変換部２１のポテンシャルの状態に従って、より意図した通りに電荷の流れが発生するような配置に設定してもよい。 As shown in FIG. 2, the structure 23 is arranged in a region where the electric field is concentrated in the vicinity of the transfer transistors 22-1 and 22-2, and the transfer transistors 22-1 and 22-2 are arranged on the surface side of the semiconductor substrate 12. It is provided so as to divide the space. Further, the structure 23 may be arranged so that a charge flow is generated more as intended according to the potential state of the photoelectric conversion unit 21.
　また、画素１３には、光電変換部２１に溜まっている電荷を排出するためのオーバーフローゲート２４が設けられており、構造物２３の配置は、オーバーフローゲート２４から所定間隔だけ離れた位置に設定される。これにより、画素１３は、オーバーフローゲート２４から電荷を排出する際に、構造物２３が排出の妨げとなることを回避することができる。つまり、構造物２３がオーバーフローゲート２４の近傍に配置される構造では、オーバーフローゲート２４から電荷を排出し難くなることが想定され、画素１３は、そのような構造とならない構成となっている。 Further, the pixel 13 is provided with an overflow gate 24 for discharging the electric charge accumulated in the photoelectric conversion unit 21, and the arrangement of the structure 23 is set at a position separated from the overflow gate 24 by a predetermined interval. The charge. As a result, the pixel 13 can prevent the structure 23 from hindering the discharge when the charge is discharged from the overflow gate 24. That is, in the structure in which the structure 23 is arranged in the vicinity of the overflow gate 24, it is assumed that it becomes difficult to discharge the electric charge from the overflow gate 24, and the pixel 13 does not have such a structure.
　以上のように構成されるセンサ素子１１は、構造物２３を設ける構造とすることで、電荷が意図した方向に対して反対側に移動するようなことを防止することができる。これにより、センサ素子１１は、Cmodを高めることができるとともに、PDNUを大幅に改善することができる。従って、センサ素子１１は、測定結果に誤差が発生することを抑制することができる結果、より測定精度の向上を図ることができる。 The sensor element 11 configured as described above has a structure in which the structure 23 is provided, so that it is possible to prevent the electric charge from moving to the opposite side with respect to the intended direction. As a result, the sensor element 11 can increase the Cmod and significantly improve the PDNU. Therefore, the sensor element 11 can suppress the occurrence of an error in the measurement result, and as a result, the measurement accuracy can be further improved.
　また、センサ素子１１は、半導体基板１２の表面側に設けられた構造物２３によって半導体基板１２の深くまで届く赤外光が反射し、その反射光も光電変換部２１において光電変換される。これにより、センサ素子１１は、量子効率Qeを向上させる効果を得ることができる。 Further, in the sensor element 11, infrared light that reaches deep into the semiconductor substrate 12 is reflected by the structure 23 provided on the surface side of the semiconductor substrate 12, and the reflected light is also photoelectrically converted by the photoelectric conversion unit 21. As a result, the sensor element 11 can obtain the effect of improving the quantum efficiency Qe.
　なお、センサ素子１１において瞳補正を行う場合は、画素１３の位置に従ってオンチップマイクロレンズ１４の位置を調整するだけでよい。つまり、センサ素子１１では、構造物２３の配置を変更せずに瞳補正に対応することができる。 When performing pupil correction in the sensor element 11, it is only necessary to adjust the position of the on-chip microlens 14 according to the position of the pixel 13. That is, the sensor element 11 can cope with the pupil correction without changing the arrangement of the structure 23.
　＜センサ素子の第２の構成例＞
　図３は、本技術を適用したセンサ素子の第２の実施の形態の構成例を示す図である。なお、図３に示すセンサ素子１１Ａにおいて、図１のセンサ素子１１と共通する構成については、同一の符号を付し、その詳細な説明は省略する。また、画素１３Ａの平面的なレイアウトは、図２に示したレイアウトと同様である。 <Second configuration example of sensor element>
FIG. 3 is a diagram showing a configuration example of a second embodiment of the sensor element to which the present technique is applied. In the sensor element 11A shown in FIG. 3, the same reference numerals are given to the configurations common to the sensor element 11 of FIG. 1, and detailed description thereof will be omitted. Further, the planar layout of the pixel 13A is the same as the layout shown in FIG.
　図３に示すように、センサ素子１１Ａは、画素１３Ａに設けられる構造物２３Ａの形状が、図１の構造物２３の形状と異なっている点で、図１のセンサ素子１１と異なる構成となっており、その他の点で共通する構成となっている。 As shown in FIG. 3, the sensor element 11A has a configuration different from that of the sensor element 11 of FIG. 1 in that the shape of the structure 23A provided in the pixel 13A is different from the shape of the structure 23 of FIG. It has a common structure in other respects.
　例えば、図１の構造物２３は、矩形形状の断面形状であったのに対し、構造物２３Ａは、画素１３Ａの中央から転送トランジスタ２２－１および２２－２それぞれに電荷が向かう流れの方向に沿って傾斜するテーパー面を有する逆三角形形状の断面形状となっている。つまり、構造物２３Ａは、半導体基板１２を表面側から掘り込む際に、掘り込み深さが深くなるのに従って掘り込み幅が狭くなるように形成されたトレンチに、酸化物が埋め込まれた構成となっている。 For example, the structure 23 in FIG. 1 has a rectangular cross-sectional shape, whereas the structure 23A has a flow direction in which charges are directed from the center of the pixel 13A to the transfer transistors 22-1 and 22-2, respectively. It has an inverted triangular cross-sectional shape with a tapered surface that slopes along it. That is, the structure 23A has a structure in which an oxide is embedded in a trench formed so that when the semiconductor substrate 12 is dug from the surface side, the digging depth becomes deeper and the digging width becomes narrower. It has become.
　このように、センサ素子１１Ａは、テーパー面を有する構造物２３Ａがセンサ素子１１Ａに設けられる構成とすることによって、転送トランジスタ２２－１および２２－２それぞれに対して、より電荷が向かい易くなる構成とすることができる。即ち、転送トランジスタ２２－１がオンとなったときには、転送トランジスタ２２－１に向かってより電荷が流れ易くなり、転送トランジスタ２２－２がオンとなったときには、転送トランジスタ２２－２に向かってより電荷が流れ易くなる。これにより、センサ素子１１Ｂは、図１のセンサ素子１１よりも意図した通りに電荷の流れが発生することを期待することができ、さらなる測定精度の向上を図ることができる。 As described above, the sensor element 11A has a structure in which the structure 23A having a tapered surface is provided in the sensor element 11A, so that the electric charge can be more easily directed to each of the transfer transistors 22-1 and 22-2. Can be. That is, when the transfer transistor 22-1 is turned on, the charge is more likely to flow toward the transfer transistor 22-1, and when the transfer transistor 22-2 is turned on, the charge is more toward the transfer transistor 22-2. Charges flow easily. As a result, the sensor element 11B can be expected to generate a charge flow as intended as compared with the sensor element 11 in FIG. 1, and the measurement accuracy can be further improved.
　また、センサ素子１１Ａは、図１の構造物２３と比較して、構造物２３Ａによる赤外光の反射面積が増加することになるので、さらなる量子効率Qeの向上を期待することができる。 Further, since the sensor element 11A has an increased reflection area of infrared light by the structure 23A as compared with the structure 23 in FIG. 1, further improvement in quantum efficiency Qe can be expected.
　＜センサ素子の第３の構成例＞
　図４は、本技術を適用したセンサ素子の第３の実施の形態の構成例を示す図である。なお、図４に示すセンサ素子１１Ｂにおいて、図１のセンサ素子１１と共通する構成については、同一の符号を付し、その詳細な説明は省略する。 <Third configuration example of the sensor element>
FIG. 4 is a diagram showing a configuration example of a third embodiment of the sensor element to which the present technique is applied. In the sensor element 11B shown in FIG. 4, the same reference numerals are given to the configurations common to the sensor element 11 of FIG. 1, and detailed description thereof will be omitted.
　図４に示すように、センサ素子１１Ｂは、画素１３Ｂに設けられる転送トランジスタ２２Ｂ－１および２２Ｂ－２並びに構造物２３Ｂの形状が、図１の転送トランジスタ２２－１および２２－２並びに構造物２３の形状と異なっている点で、図１のセンサ素子１１と異なる構成となっており、その他の点で共通する構成となっている。また、画素１３Ｂの平面的なレイアウトは、図２に示したレイアウトと同様である。 As shown in FIG. 4, in the sensor element 11B, the shapes of the transfer transistors 22B-1 and 22B-2 and the structure 23B provided in the pixel 13B are the same as those of the transfer transistors 22-1 and 22-2 and the structure 23 in FIG. It has a different configuration from the sensor element 11 in FIG. 1 in that it differs from the shape of the above, and has a configuration common to other points. Further, the planar layout of the pixel 13B is the same as the layout shown in FIG.
　例えば、図１の転送トランジスタ２２－１および２２－２は、半導体基板１２の表面にゲート電極が積層されるように形成されていたのに対し、転送トランジスタ２２Ｂ－１および２２Ｂ－２は、半導体基板１２の表面を掘り込んでゲート電極が配置されるように形成される。さらに、転送トランジスタ２２Ｂ－１および２２Ｂ－２が半導体基板１２の所定の深さまで埋め込まれて形成される分だけ、構造物２３Ｂは、図１の構造物２３よりも深く形成された構成となっている。 For example, the transfer transistors 22-1 and 22-2 of FIG. 1 are formed so that the gate electrodes are laminated on the surface of the semiconductor substrate 12, whereas the transfer transistors 22B-1 and 22B-2 are semiconductors. It is formed so that the gate electrode is arranged by digging the surface of the substrate 12. Further, the structure 23B is formed deeper than the structure 23 of FIG. 1 by the amount that the transfer transistors 22B-1 and 22B-2 are embedded and formed to a predetermined depth of the semiconductor substrate 12. There is.
　例えば、転送トランジスタ２２－１および２２－２のゲート電極が、0.3μｍの深さで設けられる場合、構造物２３Ｂは、図１の構造物２３よりも0.3μｍ深い形状にすることが好ましい。 For example, when the gate electrodes of the transfer transistors 22-1 and 22-2 are provided at a depth of 0.3 μm, it is preferable that the structure 23B has a shape 0.3 μm deeper than the structure 23 of FIG.
　このように、センサ素子１１Ｂは、半導体基板１２の表面から埋め込まれて設けられるゲート電極を有する転送トランジスタ２２Ｂ－１および２２Ｂ－２によって、転送トランジスタ２２Ｂ－１および２２Ｂ－２をオンにしたときにポテンシャルの影響が及ぶ範囲を、より深くすることができる。これにより、センサ素子１１Ｂは、転送トランジスタ２２Ｂ－１および２２Ｂ－２それぞれをオンにしたときに、さらに意図した通りに電荷の流れが発生する効果を得ることができ、さらなる測定精度の向上を図ることができる。 As described above, when the transfer transistors 22B-1 and 22B-2 are turned on by the transfer transistors 22B-1 and 22B-2 having the gate electrodes embedded from the surface of the semiconductor substrate 12 in the sensor element 11B. The range affected by the potential can be deepened. As a result, the sensor element 11B can obtain the effect of generating a charge flow as intended when the transfer transistors 22B-1 and 22B-2 are turned on, respectively, and further improve the measurement accuracy. be able to.
　また、センサ素子１１Ｂにおいても、図１のセンサ素子１１と同様に、構造物２３Ｂを設けることによって、量子効率Qeを向上させる効果を得ることができる。 Further, in the sensor element 11B as well, the effect of improving the quantum efficiency Qe can be obtained by providing the structure 23B as in the sensor element 11 of FIG.
　＜センサ素子の第４の構成例＞
　図５は、本技術を適用したセンサ素子の第４の実施の形態の構成例を示す図である。なお、図５に示すセンサ素子１１Ｃにおいて、図１のセンサ素子１１と共通する構成については、同一の符号を付し、その詳細な説明は省略する。 <Fourth configuration example of sensor element>
FIG. 5 is a diagram showing a configuration example of a fourth embodiment of the sensor element to which the present technique is applied. In the sensor element 11C shown in FIG. 5, the same reference numerals are given to the configurations common to the sensor element 11 in FIG. 1, and detailed description thereof will be omitted.
　図５に示すように、センサ素子１１Ｃは、画素１３Ｃに設けられる転送トランジスタ２２Ｃ－１および２２Ｃ－２の形状が、図１の転送トランジスタ２２－１および２２－２の形状と異なっている。さらに、センサ素子１１Ｃは、構造物２３が設けられていない点で、図１のセンサ素子１１と異なる構成となっており、その他の点で共通する構成となっている。 As shown in FIG. 5, in the sensor element 11C, the shapes of the transfer transistors 22C-1 and 22C-2 provided in the pixel 13C are different from the shapes of the transfer transistors 22-1 and 22-2 in FIG. Further, the sensor element 11C has a configuration different from that of the sensor element 11 of FIG. 1 in that the structure 23 is not provided, and has a configuration common to other points.
　例えば、転送トランジスタ２２Ｃ－１および２２Ｃ－２は、図４の転送トランジスタ２２Ｂ－１および２２Ｂ－２と同様に、半導体基板１２の表面を掘り込んでゲート電極が配置されるように形成される。これにより、センサ素子１１Ｃは、センサ素子１１Ｂと同様に、転送トランジスタ２２Ｃ－１および２２Ｃ－２をオンにしたときにポテンシャルの影響が及ぶ範囲を、より深くすることができる。 For example, the transfer transistors 22C-1 and 22C-2 are formed so that the gate electrodes are arranged by digging the surface of the semiconductor substrate 12, similarly to the transfer transistors 22B-1 and 22B-2 of FIG. As a result, the sensor element 11C, like the sensor element 11B, can deepen the range affected by the potential when the transfer transistors 22C-1 and 22C-2 are turned on.
　従って、センサ素子１１Ｃは、図１に示したような構造物２３を設けないような構成としても、転送トランジスタ２２Ｃ－１および２２Ｃ－２それぞれをオンにしたときに、意図した通りに電荷の流れが発生することを期待することができる。これにより、センサ素子１１Ｃは、測定精度の向上を図ることができる。 Therefore, even if the sensor element 11C is configured so as not to provide the structure 23 as shown in FIG. 1, when the transfer transistors 22C-1 and 22C-2 are turned on, the charge flow is as intended. Can be expected to occur. As a result, the sensor element 11C can improve the measurement accuracy.
　＜電子機器の構成例＞
　上述したようなセンサ素子１１は、例えば、TOFを利用して測距を行って、測距画像を取得する測定装置などの電子機器に適用することができる。 <Example of electronic device configuration>
The sensor element 11 as described above can be applied to an electronic device such as a measuring device that measures a distance using a TOF and acquires a distance measurement image.
　図６は、電子機器に搭載される撮像装置の構成例を示すブロック図である。 FIG. 6 is a block diagram showing a configuration example of an image pickup device mounted on an electronic device.
　図６に示すように、撮像装置１０１は、光学系１０２、撮像素子１０３、信号処理回路１０４、モニタ１０５、およびメモリ１０６を備えて構成され、静止画像および動画像を撮像可能である。 As shown in FIG. 6, the image pickup device 101 includes an optical system 102, an image pickup element 103, a signal processing circuit 104, a monitor 105, and a memory 106, and can capture still images and moving images.
　光学系１０２は、１枚または複数枚のレンズを有して構成され、被写体からの像光（入射光）を撮像素子１０３に導き、撮像素子１０３の受光面（センサ部）に結像させる。 The optical system 102 is configured to have one or a plurality of lenses, and guides the image light (incident light) from the subject to the image pickup element 103 to form an image on the light receiving surface (sensor unit) of the image pickup element 103.
　撮像素子１０３としては、上述したセンサ素子１１が適用される。撮像素子１０３には、光学系１０２を介して受光面に結像される像に応じて、一定期間、電子が蓄積される。そして、撮像素子１０３に蓄積された電子（例えば、転送トランジスタ２２－１および２２－２それぞれに振り分けられた電荷）に応じた信号が信号処理回路１０４に供給される。 As the image pickup element 103, the sensor element 11 described above is applied. Electrons are accumulated in the image pickup device 103 for a certain period of time according to the image formed on the light receiving surface via the optical system 102. Then, a signal corresponding to the electrons stored in the image pickup device 103 (for example, the electric charge distributed to each of the transfer transistors 22-1 and 22-2) is supplied to the signal processing circuit 104.
　信号処理回路１０４は、撮像素子１０３から出力された画素信号に対して各種の信号処理を施す。信号処理回路１０４が信号処理を施すことにより得られた測距画像（画像データ）は、モニタ１０５に供給されて表示されたり、メモリ１０６に供給されて記憶（記録）されたりする。 The signal processing circuit 104 performs various signal processing on the pixel signal output from the image pickup device 103. The ranging image (image data) obtained by performing signal processing by the signal processing circuit 104 is supplied to the monitor 105 and displayed, or supplied to the memory 106 and stored (recorded).
　このように構成されている撮像装置１０１では、上述したセンサ素子１１を適用することで、例えば、より精度の高い測距画像を撮像することができる。 In the image pickup apparatus 101 configured in this way, by applying the sensor element 11 described above, for example, a more accurate ranging image can be captured.
　＜構成の組み合わせ例＞
　なお、本技術は以下のような構成も取ることができる。
（１）
　半導体基板の裏面側から照射された光を光電変換する光電変換部と、
　前記半導体基板の表面側に設けられ、前記光電変換部で発生した電荷を転送する第１の転送部および第２の転送部と、
　前記半導体基板の表面から所定の深さとなる構造で、前記第１の転送部および前記第２の転送部の間に配置される構造部と
　を備えるセンサ素子。
（２）
　前記構造部の深さは、前記第１の転送部または前記第２の転送部による電荷の転送がオンにされたときに、前記第１の転送部または前記第２の転送部それぞれのポテンシャルの影響が及ぶ範囲に設定される
　上記（１）に記載のセンサ素子。
（３）
　前記構造部は、前記半導体基板の表面を前記所定の深さまで彫り込んで形成されるトレンチに酸化物が埋め込まれた構造である
　上記（１）または（２）に記載のセンサ素子。
（４）
　前記構造部は、平面視して、前記第１の転送部および前記第２の転送部の間を分断する位置に設けられ、かつ、前記光電変換部に蓄積されている電荷を排出する排出部から所定間隔だけ離れた位置に配置される
　上記（１）から（３）までのいずれかに記載のセンサ素子。
（５）
　前記半導体基板の裏面側に積層され、前記光電変換部を有する画素ごとに光を集光するオンチップマイクロレンズをさらに備え、
　前記オンチップマイクロレンズの位置を調整することで瞳補正に対応する
　上記（１）から（４）までのいずれかに記載のセンサ素子。
（６）
　前記構造部は、前記第１の転送部および前記第２の転送部それぞれに向かう電荷の流れの方向に沿って傾斜するテーパー面を有する断面形状である
　上記（１）から（５）までのいずれかに記載のセンサ素子。
（７）
　前記第１の転送部および前記第２の転送部それぞれは、前記半導体基板の表面から埋め込まれて設けられるゲート電極を有して構成される
　上記（１）から（６）までのいずれかに記載のセンサ素子。
（８）
　前記構造部は、前記第１の転送部および前記第２の転送部のゲート電極の埋め込み深さに応じて深く形成される
　上記（７）に記載のセンサ素子。
（９）
　半導体基板の裏面側から照射された光を光電変換する光電変換部と、
　前記半導体基板の表面側に設けられ、前記光電変換部で発生した電荷を転送する第１の転送部および第２の転送部と、
　前記半導体基板の表面から所定の深さとなる構造で、前記第１の転送部および前記第２の転送部の間に配置される構造部と
　を有するセンサ素子を備える電子機器。 <Example of configuration combination>
The present technology can also have the following configurations.
(1)
A photoelectric conversion unit that photoelectrically converts the light emitted from the back surface side of the semiconductor substrate, and
A first transfer unit and a second transfer unit, which are provided on the surface side of the semiconductor substrate and transfer electric charges generated by the photoelectric conversion unit,
A sensor element having a structure having a predetermined depth from the surface of the semiconductor substrate and including a structural portion arranged between the first transfer unit and the second transfer unit.
(2)
The depth of the structural unit is the potential of each of the first transfer unit or the second transfer unit when the charge transfer by the first transfer unit or the second transfer unit is turned on. The sensor element according to (1) above, which is set within the range of influence.
(3)
The sensor element according to (1) or (2) above, wherein the structural portion has a structure in which an oxide is embedded in a trench formed by engraving the surface of the semiconductor substrate to the predetermined depth.
(4)
The structural unit is provided at a position that divides between the first transfer unit and the second transfer unit in a plan view, and is a discharge unit that discharges the electric charge accumulated in the photoelectric conversion unit. The sensor element according to any one of (1) to (3) above, which is arranged at a position separated from the above by a predetermined interval.
(5)
Further, an on-chip microlens laminated on the back surface side of the semiconductor substrate and condensing light for each pixel having the photoelectric conversion unit is further provided.
The sensor element according to any one of (1) to (4) above, which corresponds to pupil correction by adjusting the position of the on-chip microlens.
(6)
The structural portion has a cross-sectional shape having a tapered surface inclined along the direction of charge flow toward each of the first transfer portion and the second transfer portion. Any of the above (1) to (5). The sensor element described in Crab.
(7)
The above (1) to (6), wherein each of the first transfer unit and the second transfer unit is configured to have a gate electrode embedded and provided from the surface of the semiconductor substrate. Sensor element.
(8)
The sensor element according to (7) above, wherein the structural portion is formed deeply according to the embedding depth of the gate electrodes of the first transfer portion and the second transfer portion.
(9)
A photoelectric conversion unit that photoelectrically converts the light emitted from the back surface side of the semiconductor substrate, and
A first transfer unit and a second transfer unit, which are provided on the surface side of the semiconductor substrate and transfer electric charges generated by the photoelectric conversion unit,
An electronic device having a structure having a predetermined depth from the surface of the semiconductor substrate and having a sensor element having a structure portion arranged between the first transfer unit and the second transfer unit.
　なお、本実施の形態は、上述した実施の形態に限定されるものではなく、本開示の要旨を逸脱しない範囲において種々の変更が可能である。また、本明細書に記載された効果はあくまで例示であって限定されるものではなく、他の効果があってもよい。 Note that the present embodiment is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present disclosure. Further, the effects described in the present specification are merely exemplary and not limited, and other effects may be used.
　１１　センサ素子，　１２　半導体基板，　１３　画素，　１４　オンチップマイクロレンズ，　１５　遮光部，　２１　光電変換部，　２２－１および２２－２　転送トランジスタ，　２３　構造物，　２４　オーバーフローゲート 11 sensor elements, 12 semiconductor substrates, 13 pixels, 14 on-chip microlenses, 15 light-shielding parts, 21 photoelectric conversion parts, 22-1 and 22-2 transfer transistors, 23 structures, 24 overflow gates.

Claims (9)

  1. 　半導体基板の裏面側から照射された光を光電変換する光電変換部と、
    　前記半導体基板の表面側に設けられ、前記光電変換部で発生した電荷を転送する第１の転送部および第２の転送部と、
    　前記半導体基板の表面から所定の深さとなる構造で、前記第１の転送部および前記第２の転送部の間に配置される構造部と
    　を備えるセンサ素子。     A photoelectric conversion unit that photoelectrically converts the light emitted from the back surface side of the semiconductor substrate, and
    A first transfer unit and a second transfer unit, which are provided on the surface side of the semiconductor substrate and transfer the electric charge generated by the photoelectric conversion unit,
    A sensor element having a structure having a predetermined depth from the surface of the semiconductor substrate and including a structural portion arranged between the first transfer unit and the second transfer unit.
  2. 　前記構造部の深さは、前記第１の転送部または前記第２の転送部による電荷の転送がオンにされたときに、前記第１の転送部または前記第２の転送部それぞれのポテンシャルの影響が及ぶ範囲に設定される
    　請求項１に記載のセンサ素子。     The depth of the structural unit is the potential of each of the first transfer unit or the second transfer unit when the charge transfer by the first transfer unit or the second transfer unit is turned on. The sensor element according to claim 1, which is set within the range of influence.
  3. 　前記構造部は、前記半導体基板の表面を前記所定の深さまで彫り込んで形成されるトレンチに酸化物が埋め込まれた構造である
    　請求項１に記載のセンサ素子。     The sensor element according to claim 1, wherein the structural portion has a structure in which an oxide is embedded in a trench formed by engraving the surface of the semiconductor substrate to the predetermined depth.
  4. 　前記構造部は、平面視して、前記第１の転送部および前記第２の転送部の間を分断する位置に設けられ、かつ、前記光電変換部に蓄積されている電荷を排出する排出部から所定間隔だけ離れた位置に配置される
    　請求項１に記載のセンサ素子。     The structural unit is provided at a position that divides between the first transfer unit and the second transfer unit in a plan view, and is a discharge unit that discharges the electric charge accumulated in the photoelectric conversion unit. The sensor element according to claim 1, which is arranged at a position separated from the sensor element by a predetermined interval.
  5. 　前記半導体基板の裏面側に積層され、前記光電変換部を有する画素ごとに光を集光するオンチップマイクロレンズをさらに備え、
    　前記オンチップマイクロレンズの位置を調整することで瞳補正に対応する
    　請求項１に記載のセンサ素子。     An on-chip microlens laminated on the back surface side of the semiconductor substrate and condensing light for each pixel having the photoelectric conversion unit is further provided.
    The sensor element according to claim 1, which corresponds to pupil correction by adjusting the position of the on-chip microlens.
  6. 　前記構造部は、前記第１の転送部および前記第２の転送部それぞれに向かう電荷の流れの方向に沿って傾斜するテーパー面を有する断面形状である
    　請求項１に記載のセンサ素子。     The sensor element according to claim 1, wherein the structural portion has a cross-sectional shape having a tapered surface inclined along the direction of charge flow toward each of the first transfer portion and the second transfer portion.
  7. 　前記第１の転送部および前記第２の転送部それぞれは、前記半導体基板の表面から埋め込まれて設けられるゲート電極を有して構成される
    　請求項１に記載のセンサ素子。     The sensor element according to claim 1, wherein each of the first transfer unit and the second transfer unit has a gate electrode embedded and provided from the surface of the semiconductor substrate.
  8. 　前記構造部は、前記第１の転送部および前記第２の転送部のゲート電極の埋め込み深さに応じて深く形成される
    　請求項７に記載のセンサ素子。     The sensor element according to claim 7, wherein the structural portion is formed deeply according to the embedding depth of the gate electrodes of the first transfer portion and the second transfer portion.
  9. 　半導体基板の裏面側から照射された光を光電変換する光電変換部と、
    　前記半導体基板の表面側に設けられ、前記光電変換部で発生した電荷を転送する第１の転送部および第２の転送部と、
    　前記半導体基板の表面から所定の深さとなる構造で、前記第１の転送部および前記第２の転送部の間に配置される構造部と
    　を有するセンサ素子を備える電子機器。     A photoelectric conversion unit that photoelectrically converts the light emitted from the back surface side of the semiconductor substrate, and
    A first transfer unit and a second transfer unit, which are provided on the surface side of the semiconductor substrate and transfer the electric charge generated by the photoelectric conversion unit,
    An electronic device having a structure having a predetermined depth from the surface of the semiconductor substrate and having a sensor element having a structure portion arranged between the first transfer unit and the second transfer unit.
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