Photon Factory Activity Report 2005 #23Part B (2006)
Surface and Interface

18B/2005R12,2005R25

Microstructure Characterization of Er2O3 Thin Films by Grazing incidence X-ray
Diffraction
Xianying XUE, Yuzhu WANG, Quanjie JIA, Yu Chen, Xiaoming JIANG*
Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Beijing 100049
three crystal planes of {220} respectively whoseoinclinations are all 60 , the erbium thin film ismonocrystalline and the orientation relationship is Er2O3(110) // Si (111) and the plane 400 is parallel to the plane
220 of the Si substrate. From fig. 1(b) we can find that theangular differences between the Bragg diffraction peaksof the substrate and the thin film are different which canbe concluded that there exists strain in different
orientations, and the accurate thickness, density, androughness were obtained by simulating the experimental
reflectivity patterns.
two-domain-rot90-th2th-1

0.1(-440)a(004)
0.01

b

I(a.u.)

I (a.u.)Introduction
With the development of silicon based integrate circuit(IC) technology more and more attention was paid infinding the high-k gate dielectric films that can replace forthe traditional thin silicon oxide films. The epitaxial
growth of the rare earth (RE) metal oxide films has
gained from Si-based industry recently because thesefilms have high dielectric constant, good thermodynamic
stability, etc. Erbium oxide (Er2O3), with high dielectric
constant, wide band gap and relatively large conduction
band offset, maybe a promising candidate as suitable gate
dielectric layer in complement ary-metal-oxide-semiconductor (CMOS) device materials.
In this investigation, we studied the microstructurecharacterization of epitaxially grown Er2O3 thin films on
the Si substrate by using grazing incidence x-ray
diffraction (GIXD).

0.01

1E-3

1E-3

1E-43035404550

3035402Theta(deg)Results and Discussion
810100710

Phi-scan @ 2gama=48.3480(202)610
Peak I

Peak II

Peak III

24.05

84.25

144.4

4020(440)

510I(a.u.)

60
I(a.u.)(220)

4(404)(022)(044)

10310210a1

100b0

20

4060

80

100 120 140 160 180

Phi (deg)

01045.5 46.0 46.5 47.0 47.5 48.0 48.5 49.0 49.5 50.0 50.5
2 Theta (deg)Fig. 1: Phi scan from 0 toπ(a) and longitude scansaround each Bragg peaks of thin film grown onthe Si(111)Fig. 1 shows the Phi scan from 0 to π and the longitudescans around each Bragg peaks of sample Er2O3 (110) // Si(111). The results shows that Bragg diffraction occurs in76

Users' Report5055

B###1000100

10Si(004)

1I(a.u.)Experimental
Er2O3 films were deposited in a multi-chamber Si
molecule beam epitaxy (MBE) system with a base-9
pressure of about 3 x 10 Torr, by using a metallic erbium
source. 1.5-in. p-type Si(111) and Si(001) wafers withresistivity of 2-10Ωcm were used as substrates. Clean
Si(111) and Si(001) surfaces were prepared for the growthof Er2O3 films. The clean surfaces were prepared bydipping them in dilute HF solution after cleaned with
Shiraki method and then desorping the adsorbed H atoms
at high temperatures in vacuum. The growth was carriedout at a temperature of 700°C with oxygen partial-6
pressure of about 7 x 10 Torr. Film surface morphologies
were obtained using atomic force microscopy (AFM).

452 Theta (deg)c0.1

Er2O3( 440)
0.01
1E-3

1E-4
45

505560657075

2Theta(deg)Fig. 2. Results of grazing incidence x-ray diffraction oferbium thin film grown on Si (001) substrate.
Fig. 2 shows the results of grazing incidence x-ray
diffraction of erbium sample grown on the Si (001)substrate. Two ordered domains which are vertical eachother were found from the results, and two Bragg
diffraction peaks occur around the diffraction peak of theSi substrate. Two vertical ordered domain are (-440),(004)(a) and (4-40), (-400)(b). The lattice mismatch ∆dand the strain (ε), the maximum intensity ratio, FWHM
and the ordered-domain sizes can be obtained from theresults, by which we can characterize the domain profile
accurately. The ordered domain occurred in the erbium
thin film grown by MBE is an interesting phenomenon.
Our research will afford some instructions in finding thepromising candidates for the conventional SiO2 dielectricmaterial.

*

jiangxm@ihep.ac.cn