CN110518026A - It is a kind of using TSV technology without back electrode photodetector array structure and preparation method thereof - Google Patents

Abstract

The invention discloses a back-electrode-free photodetector array structure using TSV technology and a preparation method thereof, comprising a semiconductor silicon substrate, a P+ type isolation groove and an N+ doped region; the P+ type isolation groove is arranged on a semiconductor silicon substrate The front side of the bottom; the N+ doped region is arranged on the front and back sides of the semiconductor silicon substrate; the P+ type isolation grooves on the front side of the semiconductor silicon substrate and the N+ doped regions are alternately arranged at intervals; the front side of the semiconductor silicon substrate An electrode cathode is provided on the N+ doped region; an electrode anode is provided at the upper end of the P+ type isolation tank; an anti-reflection film is also provided on the front and back of the semiconductor silicon substrate; the electrode cathode and the electrode anode are arranged on the same side In the present invention, the electrodes are arranged on the same side, which meets the development requirements of light and thin detector devices, reduces production costs, and uses TSV technology for the N+ doped regions on the front and back of the semiconductor silicon substrate to realize the connection between the N+ doped regions on the front and back sides , which is beneficial to carrier collection and reduces crosstalk.

Description

A photodetector array structure without back electrode using TSV technology and its preparation method

technical field

The invention relates to a back-electrode-free photodetector array structure using TSV technology and a preparation method thereof, belonging to the technical field of semiconductor photodetectors.

Background technique

The semiconductor photodetector array generates visible light in the scintillator through direct incident light or X-rays, and generates non-equilibrium carriers in the semiconductor to detect the incident light. The key parameters to measure the performance of the photodetector array include resolution, dark current, Signal-to-noise ratio, readout speed, and charge crosstalk between pixels, etc.

At present, mainstream photodetectors adopt a PIN structure with a back electrode, and the anode and cathode of the detector are respectively located on the front and back of the detector, which does not take advantage of device thinning and cost reduction; in addition, in order to reduce the crosstalk of the detector array, usually Using PN junction isolation, deep trench isolation and other technologies, the effect is not good or the process is difficult.

Contents of the invention

In view of the above-mentioned technical problems, the object of the present invention is to propose a back-electrode-free photodetector array structure using TSV technology and its preparation method, which can reduce dark current, facilitate carrier collection and reduce crosstalk, reduce manufacturing cost.

The technical solution of the present invention is achieved in this way: a back-electrode photodetector array structure using TSV technology, including a semiconductor silicon substrate, a P+ type isolation groove and an N+ doped region; the P+ type isolation groove is arranged on The front side of the semiconductor silicon substrate; the N+ doped region is arranged on the front and back sides of the semiconductor silicon substrate; the P+ type isolation grooves and N+ doped regions on the front side of the semiconductor silicon substrate are alternately arranged at intervals; the semiconductor silicon substrate An electrode cathode is provided on the N+ doped area on the front side of the bottom; an electrode anode is provided at the upper end of the P+ type isolation tank; an anti-reflection film is also provided on the front and back of the semiconductor silicon substrate; the electrode cathode and the electrode anode are both provided on the same side.

Preferably, the anti-reflection film adopts SiN or SiO ₂ thin film or SiN/SiO ₂ double-layer thin film structure.

Preferably, the antireflection film has a thickness of 50-100 nm.

Preferably, the semiconductor silicon substrate is divided into an N-type silicon substrate and a P-type silicon substrate.

Preferably, the N+ doped regions on the front side and the back side of the semiconductor silicon substrate are connected through vertical via holes.

A preparation method of a photodetector array structure without a back electrode using TSV technology. First, a suitable semiconductor silicon substrate is selected, and a diffusion process or ion implantation technology is used to dope the front side of the semiconductor silicon substrate to form P+ type isolation grooves and N+ Doped region, doping on the back to form N+ doped region; then, use SiN or SiO ₂ thin film or SiN/SiO ₂ double-layer thin film structure on the front of the semiconductor silicon substrate to form an anti-reflection film, and use SiN or SiO ₂ thin film or The SiN/SiO ₂ double-layer film structure is passivated, and the thickness is controlled at 50-100nm; next, the electrode cathode and electrode anode are installed on the same side of the semiconductor silicon substrate to complete the processing of the entire structure.

Preferably, the N+ doped regions on the front and back of the semiconductor silicon substrate adopt TSV technology to realize the connection of the N+ doped regions on the front and back.

Due to the application of the above-mentioned technical solution, the present invention has the following advantages compared with the prior art:

A back-electrode-free photodetector array structure and its preparation method adopting TSV technology of the present invention, by arranging the electrodes on the same side, meets the development requirements of light and thin detector devices, reduces production costs, and integrates the front surface of the semiconductor silicon substrate with the The N+ doped region on the back uses TSV technology to realize the connection between the front and back N+ doped regions, which is beneficial to carrier collection and reduces crosstalk.

Description of drawings

Below in conjunction with accompanying drawing, technical solution of the present invention will be further described:

Accompanying drawing 1 is a kind of sectional structure schematic diagram of the back electrode photodetector array structure that adopts TSV technology of the present invention;

Accompanying drawing 2 is another state cross-sectional structure schematic diagram of a kind of back electrode photodetector array structure adopting TSV technology of the present invention;

Among them: 1. Semiconductor silicon substrate; 2. P+ type isolation groove; 3. N+ doped region; 4. Electrode cathode; 5. Electrode anode; 6. Antireflection film.

Detailed ways

The present invention is described below in conjunction with accompanying drawing.

Shown in accompanying drawing 1, 2 is a kind of back electrode photodetector array structure that adopts TSV technology according to the present invention, comprises semiconductor silicon substrate 1, P+ type isolation groove 2 and N+ doped region 3; The P+ type isolation groove 2 is arranged on the front side of the semiconductor silicon substrate 1; the N+ doped region 3 is arranged on the front side and the back side of the semiconductor silicon substrate 1; the P+ type isolation groove 2 on the front side of the semiconductor silicon substrate 1 and the N+ The doped regions 3 are arranged at staggered intervals; the N+ doped region 3 on the front side of the semiconductor silicon substrate 1 is provided with an electrode cathode 4; the upper end of the P+ type isolation groove 2 is provided with an electrode anode 5; the semiconductor silicon substrate 1 An anti-reflection film 6 is also provided on the front and back; the electrode cathode 4 and the electrode anode 5 are both arranged on the same side.

In order to reduce surface recombination and dark current, the anti-reflection film 6 adopts SiN or SiO ₂ film or SiN/SiO ₂ double-layer film structure; the thickness of the anti-reflection film 6 is 50-100 nm.

The semiconductor silicon substrate 1 is divided into an N-type silicon substrate and a P-type silicon substrate. According to the difference between the N-type silicon substrate and the P-type silicon substrate, the P+ type isolation groove 2 and the The interchange of N+ doped regions 3 meets the requirements.

The N+ doped regions 3 on the front and back of the semiconductor silicon substrate 1 are connected through vertical through holes, and the TSV (Through Silicon Vias) technology is used to realize the connection between the N+ doped regions 3 on the front and back sides, and an electric field in the vertical direction can be formed. It is beneficial to carrier collection and crosstalk reduction (especially long-wavelength incident light), and TSV is realized by laser drilling technology.

A preparation method of a photodetector array structure without a back electrode using TSV technology. First, a suitable semiconductor silicon substrate 1 is selected, and a diffusion process or ion implantation technology is used to dope the front surface of the semiconductor silicon substrate 1 to form a P+ type isolation groove. 2 and N+ doped region 3, the back side is doped to form N+ doped region 3; then, SiN or _SiO2 thin film or SiN/ _SiO2 double-layer thin film structure is used on the front side of semiconductor silicon substrate 1 to form anti-reflection film 6, and the back side SiN or SiO ₂ film or SiN/SiO ₂ double-layer film structure is used for passivation, and the thickness is controlled at 50-100nm; next, electrode cathode 4 and electrode anode 5 are installed on the same side of the semiconductor silicon substrate 1 to complete the entire structure. processing.

The N+ doped regions 3 on the front and back of the semiconductor silicon substrate 1 adopt TSV technology to realize the connection of the N+ doped regions 3 on the front and back, and form an electric field in the vertical direction, which is beneficial to carrier collection and crosstalk reduction.

A back-electrode-free photodetector array structure and its preparation method adopting TSV technology of the present invention, by arranging the electrodes on the same side, meets the development requirements of light and thin detector devices, reduces production costs, and the front side of the semiconductor silicon substrate 1 The N+ doped region 3 on the back uses TSV technology to realize the connection between the front and back N+ doped regions 3, which is beneficial to carrier collection and reduces crosstalk.

The above-mentioned embodiments are only to illustrate the technical conception and characteristics of the present invention. Substantial equivalent changes or modifications shall fall within the protection scope of the present invention.

Claims (7)

1. A photodetector array structure without a back electrode using TSV technology, characterized in that: comprise a semiconductor silicon substrate, a P+ type isolation groove and an N+ doped region; the P+ type isolation groove is arranged on the semiconductor silicon substrate The front side; the N+ doped regions are arranged on the front and back sides of the semiconductor silicon substrate; the P+ type isolation grooves on the front side of the semiconductor silicon substrate and the N+ doped regions are alternately arranged; the N+ doped regions on the front side of the semiconductor silicon substrate An electrode cathode is provided on the miscellaneous area; an electrode anode is provided at the upper end of the P+ type isolation groove; an anti-reflection film is provided on the front and back of the semiconductor silicon substrate; the electrode cathode and the electrode anode are both arranged on the same side. 2. A back-electrode-free photodetector array structure using TSV technology as claimed in claim 1, characterized in that: said anti-reflection film adopts SiN or SiO ₂ thin film or SiN/SiO ₂ double-layer thin film structure. 3. A photodetector array structure without a back electrode using TSV technology as claimed in claim 1 or 2, characterized in that: the thickness of the antireflection film is 50-100 nm. 4. A photodetector array structure without a back electrode using TSV technology as claimed in claim 1, wherein the semiconductor silicon substrate is divided into an N-type silicon substrate and a P-type silicon substrate. 5. A photodetector array structure without a back electrode using TSV technology as claimed in claim 1, characterized in that: the N+ doped regions on the front and back of the semiconductor silicon substrate are connected through vertical via holes. 6. a kind of preparation method of the photodetector array structure without back electrode that adopts TSV technology as claimed in claim 1, it is characterized in that: first, select suitable semiconductor silicon substrate, adopt diffusion process or ion implantation technology in semiconductor The front side of the silicon substrate is doped to form P+ type isolation grooves and N ₊ doped regions, and the back side is doped to form N ₊ doped regions; Form an anti-reflection film, passivate the back with SiN or SiO ₂ thin film or SiN/SiO ₂ double-layer thin film structure, and control the thickness at 50-100nm; Next, install the electrode cathode and electrode anode on the same side of the semiconductor silicon substrate to complete Processing of the entire structure. 7. a kind of preparation method of the photodetector array structure without back electrode that adopts TSV technology as claimed in claim 6, is characterized in that: the N+ doped region of described semiconductor silicon substrate front and back adopts TSV technology, realizes The connection of the front and back N+ doped regions.