CN102818721A

CN102818721A - Preparation method of non-conductive sample used for X-ray photoelectron spectroscopy measurement

Info

Publication number: CN102818721A
Application number: CN2012102974023A
Authority: CN
Inventors: 崔云
Original assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Current assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Priority date: 2012-08-20
Filing date: 2012-08-20
Publication date: 2012-12-12

Abstract

The invention relates to a preparation method of a non-conductive sample used for X-ray photoelectron spectroscopy measurement. A conductive link is added around non-conductive sample test region, and the conductive link can be a coated conductive film, a plated conductive film or a closely attached conductive mask. The method provided in the invention is simple. By combing the non-conductive sample prepared by the invention with a neutralization gun in use, a surface charge effect in X-ray photoelectron spectroscopy measurement can be quickly eliminated, thus realizing accurate data measurement and reducing the analysis difficulty.

Description

The preparation method who is used for the non-conductive sample of xps measurement

Technical field

The present invention relates to xps measurement, is a kind of preparation method who is used for the non-conductive sample of xps measurement.

Technical background

When with monochromatic X-ray source irradiation non-conductive sample surperficial, photoelectron emissions causes the positive surface charge accumulation, causes peak position to move to high binding energy direction; During with the ion beam etching sample surfaces, use the Ar cation usually, also can cause the electric charge accumulation of sample surfaces, this electric charge accumulation possibly all can't be removed in a few hours, causes peak shift.

The power spectrum peak position is the key of carrying out sample analysis of components and Determination of Different Valence States, in order to obtain power spectrum peak position accurately, can take the surface is carried out the method for charge compensation, and method commonly used is to use in the electronics and compensates low-energy electron with rifle to sample surfaces.But because the difference of aspects such as the conductivity of different sample surfaces, X ray ionization cross section, surface topography; In with the rifle electronics can't balance all samples surface electric charge; The situation that neutralizes or owe to neutralize occurred, and measured power spectrum and drift about to low binding energy direction or high binding energy direction.

The another kind of method that obtains accurate power spectrum peak position is to calibrate with modal organic contaminant C 1s peak position in the vacuum system.But some sample need carry out measuring after the etching, and surface contamination layer is removed, and causes the peak position that can't find C 1s, can't calibrate with the C1s peak position.

Summary of the invention

The purpose of this invention is to provide a kind of preparation method who is used for the non-conductive sample of xps measurement, this method makes the position of the element binding energy of non-conductive sample have very high accuracy, reduces and analyzes difficulty.

Of the present invention. technical solution is following:

A kind of preparation method who is used for the non-conductive sample of xps measurement is characterized in that: this method is to increase the conduction link on every side in the non-conductive sample test section, and described conduction is linked as and is coated with conducting film, plates conducting film or is close to the conduction mask.

Technique effect of the present invention is following:

Utilize the non-conductive sample of the inventive method preparation; Near sample surfaces X-ray light spot irradiated region, increase the conduction link; Can eliminate the charged difference of sample surfaces or inhomogeneous charged; Cross neutralization with rifle in effectively overcoming or owe in the time spectrogram drift that causes, directly obtain peak position value accurately, reduce and analyze difficulty.

Description of drawings

Fig. 1 is the mask synoptic diagram before the sample plated film;

Wherein: 1 is the sample synoptic diagram; 2 is the sample surfaces mask, makes test zone avoid plating conducting film, and mask is of a size of d, 2.5mm >=d>the X-ray light spot size.

Fig. 2 removes the sample XPS measuring synoptic diagram of mask

Wherein: 3 are the monochromatization focusing X-ray; 4 are the x-ray bombardment district; 5 for removing the sample surfaces zone of mask; 6 sample surfaces zones for the plating conducting film; 7 is the electron collection lens; 8 is the hemisphere analyser; 9 is the XPS spectrum figure of Si 2p.

Fig. 3 is LiTaO ₃The crystal plain film do not plate conducting film open in power spectrum when the rifle

Fig. 4 is LiTaO ₃Power spectrum in opening behind the crystal plain film plating conducting film during with rifle

Fig. 5 Al ₂O ₃(left side: conducting film is not plated on the surface to the power spectrum of C 1s before and after the film surface ion beam etching; Right: surface plating conducting film)

Fig. 6 is Al ₂O ₃Film surface do not plate conducting film open in power spectrum when the rifle

Fig. 7 is Al ₂O ₃Power spectrum during film surface plating conducting film is opened during with rifle

Embodiment

Below in conjunction with embodiment and accompanying drawing the present invention is described further, but should limit protection scope of the present invention with this.

Preparation method of the present invention is exemplified below:

A, sample surfaces be coated with conducting film or the plating conducting film

Do mask at sample surfaces, reserve test zone, then at surfaces coated or plating conducting film.Require rete fine and close continuously; Thicknesses of layers T is preferably in 20nm, and < T < in 50 mu m ranges, should not cross thin or blocked up electric conductivity and the measurement effect of influencing; The mask size gets final product greater than the X-ray light spot size and less than 2.5mm, is difficult for the excessive test section electric charge that influences and imports.Remove the sample surfaces mask during test, connect sample surfaces conducting film and metal sample platform through metal clip or conducting resinl.

B, be close to the conduction mask at sample surfaces

To the flat samples that still will use after some measurements, can be close to the conduction mask plate of thickness on its surface less than 50um.The test microvia size that the conduction mask is reserved gets final product greater than the X-ray light spot size and less than 2.5mm, should excessively not influence the test section electric charge and import.The mask that will conduct electricity is fitted with the surface, avoids the space, during test the conduction mask should with the conducting of external metallization sample stage.

Embodiment 1

LiTaO ₃Peak position contrast before and after the plane of crystal plating conducting film.

Concrete steps are not plated conducting film LiTaO for measuring earlier ₃The surperficial composition and the peak position of crystal, surperficial composition and the peak position behind the measurement plating conducting film again.

The step that is coated with of conducting film sees also Fig. 1 earlier, with mask sample district to be tested is covered earlier, and the mask size is coated with the fine and close continuous conduction film of thickness greater than 20nm then greater than the X-ray light spot size and less than 2.5mm on the print surface.Remove the sample surfaces mask, transfer to analysis position, test point is measured due to the center, test section, as shown in Figure 2.

According to the x-ray photoelectron power spectrum canonical reference book of publishing by Perkin-Elmer company " Handbook of X-ray photoelectron spectroscopy "; When using AlK α as x-ray source; O 1s peak position is near 531eV in the metal oxide, and Ta 4d 5/2 peak position is near 230eV.

LiTaO ₃The crystal plain film do not plate conducting film open in spectrogram when the rifle as shown in Figure 3; O 1s peak position is 547.1eV; Ta 4d 5/2 peak position is 246.1eV, and peak position is compared with standard diagram obviously and moved to high binding energy direction, shows that test zone has accumulation of positive charges; Cause photoelectron kinetic energy to reduce, sample surfaces is in owes neutral condition; LiTaO ₃Spectrogram during crystal plain film plating conducting film is opened during with rifle is as shown in Figure 4, and O 1s peak position is 531.1eV, and Ta 4d 5/2 peak position is 230.6eV, peak position with reference to power spectrum peak position basically identical, show that the charged accumulation of test zone eliminates basically.

Embodiment 2

Al ₂O ₃Carry out the peak position contrast of ion etching after carrying out ion etching and plate conducting film before the film surface plating conducting film.

Concrete steps for the plating conducting film before, with the Ar ion beam to Al ₂O ₃Film surface carries out the etching of different time, tests composition and peak position after each etching.Behind the plating conducting film, carry out identical measurement at the test zone of reserving.

According to " surface analysis " of the x-ray photoelectron power spectrum canonical reference book of publishing by Perkin-Elmer company " Handbook of X-ray photoelectron spectroscopy " and Fudan University's publication, Al ₂O ₃Middle O 1s peak position is 531.6eV, and Al 2p peak position is 74.7eV, and surface contamination C 1s peak position is 284.6eV.

Use the Ar ion pair Al of energy 1000V ₂O ₃Etching is carried out in the films test zone, and etching time was respectively 50 seconds, 100 seconds, 150 seconds.

The spectrogram of etching front and rear surfaces pollution layer C 1s is as shown in Figure 5, by no obvious C 1s peak position after the visible etching of figure.

The surface do not plate conducting film open in spectrogram when the rifle as shown in Figure 6, O 1s peak position is 541.5eV after 50 seconds in etching, etching is 541.7eV after 100 seconds and 150 seconds; The Al2p peak position in the peak position of etching after 50 seconds, 100 seconds, 150 seconds near 73.1eV; Obviously drift about with the peak position of standard peak position contrast discovery O 1s, Al2p, show that sample surfaces has charged inhomogeneous gathering.

Spectrogram during plating conducting film in surface is opened during with rifle is as shown in Figure 7, and O 1s peak position is 531.5eV after 50 seconds, 100 seconds and 150 seconds in etching respectively; Al 2p peak position be 74.8eV after 50 seconds, 100 seconds, 150 seconds in etching respectively, peak position and with reference to power spectrum peak position basically identical.The peak position of O 1s, Al 2p shows that the plating conducting film has improved the conduction situation of sample, fast the surface charge accumulation of outgoing of balance photoelectron and ion beam etching initiation.

Experiment shows, the non-conductive sample of the inventive method preparation, and what effectively produce in the snap-out release sample measurement process is surperficial charged.The present invention can be applicable to the measurement of the x-ray photoelectron power spectrum of non-conductive sample, in conjunction with in use the line drift of effectively having avoided electric charging effect to cause with rifle.

Claims

1. preparation method who is used for the non-conductive sample of xps measurement is characterized in that: this method is to increase the conduction link around in the non-conductive sample test section, and described conduction is linked as and is coated with conducting film, plates conducting film or is close to the conduction mask.