CN101630713B

CN101630713B - Ultraviolet electroluminescence device based on titanium dioxide film

Info

Publication number: CN101630713B
Application number: CN200910101385XA
Authority: CN
Inventors: 马向阳; 章圆圆; 陈培良; 杨德仁
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2009-08-03
Filing date: 2009-08-03
Publication date: 2012-05-09
Anticipated expiration: 2029-08-03
Also published as: CN101630713A

Abstract

The invention discloses an ultraviolet electroluminescence device based on a titanium dioxide film. A SiO2 film, a TiO2 film and a transparent indium tin oxide (ITO) electrode are sequentially formed in the front surface of a silicon substrate from bottom to top, and an ohmic contact electrode is deposited on the back surface of the silicon substrate. The invention also discloses a method for preparing the ultraviolet electroluminescence device. The device can generate ultraviolet electroluminescence derived from the TiO2 film in bias voltage and adjust the strength of the ultraviolet electroluminescence by adjusting the thickness and the compactness of the SiO2 film. The structure and a realizing way of the device are simple, and the equipment used by the method for preparing the device is compatible with the current mature silicon device planar technology.

Description

A kind of UV electroluminescence device based on titanium deoxid film

Technical field

The present invention relates to a kind of UV electroluminescence device, be specially a kind of UV electroluminescence device based on titanium deoxid film.

Background technology

Because the development of photoelectric technology, the demand to Ultra-Violet Laser, high density storage and other short-wavelength light electric devices makes wide bandgap semiconductor receive increasing concern.TiO wherein ₂Semi-conductive energy gap is 3.2eV (387.5nm).But TiO ₂Be indirect bandgap semiconductor, so the efficient of room temperature band edge ultra-violet light-emitting very low (W.Choi, and D.W.Bahnemann, Chem.Rev.95 (1995) 69 for list of references: M.R.Hoffmann, S.T.Martin).However, people such as A.Suisalu has measured TiO at low temperatures ₂Film is positioned at ultraviolet photoluminescence peak (list of references: A.Suisalua, J.Aarikb, the H. of 3.37eV (368nm) and 3.31eV (375nm) And I.Sildosa, Thin Solid Films 336 (1998) 295).Yet, at TiO before ₂Electroluminescent report in, no matter be the liquid phase or the TiO of solid phase ₂Electroluminescent device does not all record UV electroluminescence (list of references: Y.Nakato, A.Tsumura and H.Tsubomura, J.Phys.Chem.87 (1983) 2402, R.

, R.C.Word and M.Godinez, Nanotechnology 17 (2006) 1858).The applicant is in the patent of invention of ZL200710070054.5 in the patent No., and the method for utilizing thermal oxidation Ti film is at p ⁺Prepared TiO on the-Si substrate ₂Film has obtained stronger Visible Luminescence (P.L.Chen, D.S.Li and D.R.Yang, Appl.Phys.Lett.94 (2009) 061115 for list of references: Y.Y.Zhang, X.Y.Ma).But, utilize this simple heterojunction structure can not obtain to come from TiO ₂The ultra-violet light-emitting of film.

Summary of the invention

The invention provides a kind of device of realizing based on the titanium deoxid film UV electroluminescence.

UV electroluminescence device based on titanium deoxid film of the present invention forms SiO from bottom to top successively in the front of silicon substrate ₂Film, TiO ₂Film and transparent ITO electrode are at silicon substrate backside deposition Ohm contact electrode.

Through increasing electronic barrier layer (SiO ₂), TiO ₂Electronics in the conduction band can be at TiO ₂And the accumulation significantly at the interface between the electronic barrier layer surmounts the transition of interband, thereby obtains ultra-violet light-emitting.

Described SiO ₂Film thickness is 2～100nm, regulates SiO ₂The thickness of film and density can reach the purpose of the intensity of regulating UV electroluminescence.

The preparation method of the UV electroluminescence device based on titanium deoxid film of the present invention may further comprise the steps:

1) be after P type or the N type silicon chip of 0.005-50 ohmcm cleans, to utilize thermal oxidation or electron-beam vapor deposition method deposition SiO with resistivity ₂Film;

2) at SiO ₂Utilize the method depositing Ti O of sputter, thermal oxidation or sol-gel on the film ₂Film;

3) at TiO ₂The transparent ITO of sputter on the film (Indium Tin-Oxide indium tin oxide) electrode is at silicon substrate backside deposition Ohm contact electrode.

Device of the present invention can produce under bias voltage and come from TiO ₂The UV electroluminescence of film, and can be through regulating SiO ₂The thickness of film and density are regulated the intensity of UV electroluminescence.

The invention has the advantages that: the structure and the implementation of device are simple, and equipment that this preparation of devices method is used and existing mature silicon device plane process are compatible.

Description of drawings

Fig. 1 is the sketch map that the present invention is based on the UV electroluminescence device of titanium deoxid film;

Fig. 2 is the electroluminescence spectrum that the UV electroluminescence device of the embodiment of the invention 1 obtains under different bias voltages.

Embodiment

Further specify the present invention below in conjunction with accompanying drawing.

With reference to Fig. 1, the device based on the titanium deoxid film UV electroluminescence of invention is SiO in the front of silicon substrate 1 from bottom to top successively ₂ Film 2, TiO ₂Film 3 and ITO electrode 4 have Ohm contact electrode 5 at the silicon substrate backside deposition.

Embodiment 1

Take following processing step: 1) clean the P type<100>, resistivity is that 0.005 ohmcm, size are 15 * 15mm ², thickness is 675 microns silicon chip, puts into the electron beam evaporation chamber after the cleaning, is evaporation source with the silica dioxide granule, deposit thickness is about the SiO of 10nm on silicon chip ₂Film; 2) will deposit SiO ₂The silicon chip of film is put into the reative cell of direct current reaction magnetron sputtering device, and reative cell vacuum degree is evacuated to 5 * 10 ^-3Pa; On silicon chip, utilize the method deposit thickness of reaction direct current sputtering to be about the Ti film of 100nm, when sputter, adopt Ti metallic target, 100 ℃ of underlayer temperatures, sputtering power 70W, pass to Ar (flow is 30sccm), operating pressure is 0.8Pa; 3) will be deposited on Ti film on the silicon substrate at O ₂The following 500 ℃ of heat treatment 5h of atmosphere; 4) at TiO ₂The ITO electrode that sputter 50nm is thick on the film, at the thick Al of silicon backside deposition 100nm, both areas are 10 * 10mm ²

Fig. 2 has provided different driving voltage electroluminescence (EL) spectrum down that the device that obtains through said method at room temperature records, TiO at this moment ₂Film connects negative, and the Si substrate just connects.In electroluminescence spectrum, except more weak Visible Luminescence, also exist peak position to be positioned at the ultra-violet light-emitting about 375nm, and along with the increase of voltage, electroluminescent intensity also increase thereupon.

Embodiment 2

Take following processing step: 1) clean the N type<100>, resistivity is that 0.5 ohmcm, size are 15 * 15mm ², thickness is 675 microns silicon chip, puts into annealing furnace after the cleaning at O ₂The following 800 ℃ of heat treatment 1h of atmosphere form the SiO of thick～30nm ₂Film; 2) will deposit SiO ₂The silicon chip of film is put into the reative cell of direct current reaction magnetron sputtering device, and reative cell vacuum degree is evacuated to 5 * 10 ^-3Pa; On silicon chip, utilize the method deposit thickness that reacts direct current sputtering to be about the TiO of 200nm ₂Film when sputter, adopts Ti metallic target, 300 ℃ of underlayer temperatures, sputtering power 100W, passes to O ₂With Ar mist, O ₂With the flow-rate ratio of Ar be 1: 2, operating pressure is 5Pa; 3) at TiO ₂The ITO electrode that sputter 50nm is thick on the film, at the thick Au of silicon backside deposition 100nm, both areas are 10 * 10mm ²

Embodiment 3

Take following processing step: 1) clean the P type<100>, resistivity is that 50 ohmcms, size are 15 * 15mm ², thickness is 675 microns silicon chip, puts into the electron beam evaporation chamber after the cleaning, is evaporation source with the silica dioxide granule, deposit thickness is about the SiO of 20nm on silicon chip ₂Film; 2) adopting mol ratio is butyl titanate (Ti (OBu) ₄): ethanol (EtOH): H ₂O=1: 8: 2 precursor solution, and add an amount of HCl as catalyst, utilize sol-gel process at SiO ₂Spin-on deposition thickness is about the TiO of 150nm on the film ₂Film, after the spin coating 100 ℃ of down oven dry 10 minutes, then 500 ℃ of heat treatments 2 hours under oxygen; 3) at TiO ₂The ITO electrode that sputter 50nm is thick on the film, at the thick Al of silicon backside deposition 100nm, both areas are 10 * 10mm ²

Room temperature electroluminescent (EL) spectrum of

embodiment

2 and 3 device is similar with Fig. 2.

Claims

1. UV electroluminescence device based on titanium deoxid film, it is characterized in that: in the front of silicon substrate (1) is SiO from bottom to top successively ₂Film (2), TiO ₂Film (3) and ITO electrode (4) are at silicon substrate backside deposition Ohm contact electrode (5);

Described SiO ₂Film thickness is 2～100nm.

2. preparation method based on the UV electroluminescence device of titanium deoxid film may further comprise the steps:

1) be after the silicon substrate of 0.005-50 ohmcm cleans with resistivity, deposition SiO ₂Film;

2) at SiO ₂Depositing Ti O on the film ₂Film;

3) at TiO ₂Sputter transparent ITO electrode on the film is at silicon substrate backside deposition Ohm contact electrode;

Described SiO ₂Film thickness is 2～100nm.