臺灣博碩士論文加值系統

Non-volatile semiconductor memories have attracted much attention due to the fast growing demand of portable electronic devices. In this thesis, the atomic layer deposition prepared HfO2 thin film was fabricated with TEMAH as precursor and O2 plasma as oxidant. A 7-nm thick HfO2 thin film was applied as the charge trapping layer. The significant hysteresis loops found in C-V relation indicated the exellent charge storage effect. In additon, the erase and retention characteristics were investigated and the results were satisfactory for nonvolatile memory application.
Moreover, the Au nanocrystals were embedded in HfO2 at different locations. The effect on the device was investigated. It is found that the Au nanocrystals have an influence on the device characteristics due to the field enhancement effect.

Chapter 1 Introduction 1
1.1 Introduction 1
1.2 Research motivation 4
1.3 Thesis organization 5
Chapter 2 Literature Review 6
2.1 Introduction to semiconductor memory 6
2.2 Flash memory 9
2.2.1 Basic concept 9
2.3 Emerging nonvolatile memory 15
2.3.1 FeRAM 16
2.3.2 MRAM 18
2.3.3 PCRAM 20
2.3.4 RRAM 22
2.3.5 SONOS 24
2.3.6 SOHOS 25
2.3.7 Nanocrystal memory 26
2.4 SONOS-type memory 27
2.4.1 Operation(program/erase) mechanism 27
2.4.2 Memory characteristics of SONOS-type memory 32
2.4.3 high-k oxide as blocking oxide for SONOS-type
memory application 35
Chapter 3 Methods and Experiment 36
3.1 Experimental details and procedures 36
3.1.1 Substrate RCA clean 38
3.1.2 Back-side ion implantation 38
3.1.3Thermal oxidation of tunnel oxide (SiO2) 39
3.1.4 Deposition of HfO2 layer by ALD 39
3.1.5 Au Thin Film Deposition 41
3.1.6 Deposition of blocking oxide 42
3.1.7 Rapid thermal annealing process 44
3.1.8 Metallization 45
3.2 Analysis and Measurement 47
3.2.1 C-V measurement 47
3.2.2 Erase Curve 47
3.2.3Retention Measurement 47
Chpater 4 HfO2 as Charge Trap Layer 49
4.1 Introduction 49
4.2 Results and discussion 51
4.2.1 The charging effect in MLHOS capacitor 51
4.2.2 Erase characteristics of MLHOS capacitor 57
4.2.3Charge retention characteristics in MLHOS capacitor 58
Chapter 5 Au nanocrystal’s Field enhancement effect on
HfO2 as charge trapping layer 60
5.1Introduction 60
5.2 The effects of embedded Au nanocrystals on the
charging effect 61
5.3 The effects of embedded Au nanocrystals on the erase
characteristics 68
5.4 The effects of embedded Au nanocrystals on retention
characteristics. 71
5.5 Conclusion 75

1.Roberto Bez, Emilio Camerlenghi, Alberto Modellli, and
Angelo Visconti “Introduction to Flash Memory”
Proceedings of The IEEE, Vol.91, No.4, April 2003.

2. Paolo Pavan, Roberto Bez, Piero Olivo, and Enrico
Zanoni “Flash memory cells – An overview”
Proceeding of The IEEE, Vol.85, No.8 August 1997.

3.Kinam Kim et al., 2005 VSLI-TSA pp. 88-94(2005)

4. “Samsung unwraps 40nm "charge trap flash
device”
http://www.electroiq.com/index.html

5. ITRS 2003 edition,
http://www.itrs.net/Links/2003ITRS/Home2003.htm

6. Sheng-Chih Lai, Hang-Ting Lue, Ming-Jui Yang, Ming-Jui
Yang, Jung-Yu Hsieh,Szu-Yu Wang, Tai-Bor Wu, Guang-Li
Luo, Chao-Hsin Chien, Erh-Kun Lai, Kuang-Yeu Hsieh,
Rich Liu and Chih-Yuan Lu,” BE-SONOS: A Bandgap
Engineered SONOS using Metal Gate and Al2O3 Blocking
Layer to Overcome Erase Saturation, 2007 22nd Non-
Volatile Semiconductor Memory Workshop, pp. 26-30, 2007

7. Roberto Bez, Emilio Camerlenghi, Alberto Modellli and
Angel Visconti, “Introduction to Flash Memory,
Proceedings of the IEEE, Vol. 91, No. 4, April 2003.

8. Yeargain, J. and Kuo, K. (1981) A high density floating
gate EEPROM cell. IEEE
IEDM Technical Digest. 24.

9. M. Lenzlinger, E. H. Snow, “Fowler-Nordheim
tunneling in thermal grown SiO2”, J. Appl. Phs. 40,
278 (1969).

10. Guterman, D., Rimawi, I., Chiu, T., Halvorson, R., and
McElroy, D. (1979) “An electrically alterable
nonvolatile memory cell using a floating gate
structure”. IEEE Transactions on Electron Devices. ED-
26, 576.

11.” Emerging Non-Volatile Memory Technologies”: Infineon
Technologies, MP TD NMP, PO Box 80949, 81541 Munich,
Germany :Infineon Technologies, Japan

12. M. Lines and A. Glass, “Principles and applications of
ferroelectrics and related devices”, Clarendon Press,
Oxford, 87(1977)

13. W. J. Gallagher, S. Parkin, Yu Lu, X. P. Bian, A.
Marley, K. P. Roche, R. A. Altman, S.A. Rishton, C.
Jahnes, T. M. Shaw, and Gang Xiao, “Microstructured
magnetic tunnel junctions” J. Appl. Phys. 81, 3741
(1997).Cc

14. S. Parkin, K. P. Roche, M. G. Samant, P. M. Rice, R. B.
Beyers, R. E. Scheuerlein, E. J. O’Sullivan, S. L.
Brown, J. Bucchigano, D. W. Abraham, Yu Lu, M. Rooks,P.
L. Trouilloud, R. A. Wanner, and W. J. Gallagher,
“Exchange-biased magnetic tunnel junctions and
application to nonvolatile Magneti c random
access memory”, J. Appl. Phys. 85, 5828(1999)Cc

15. S. R. Ovskinsky, “Reversible Electrical Switching
Phenomena in Disordered Structures”, Phys. Rev. Lett.
21, 1450(1968)

16. S.Seo, M.J. Lee, D.H. Seo, S.K. Choi, D.S. Suh, Y.S.
Joung, and I.K. Yoo. I.S. Byun, I.R. Hwang, S.H. Kim,
and B.H. Park “Conductivity switching
characteristics and reset currents in NiO films”.
Appl. Phys. Lett. 86, 093509 (2005)

17. Genrikh B. Stefanovich, Choong-Rae Cho, Eun-Hong Lee,
Inkyenong Yoo “Nonvolatile resistance switching in
amorphous In-Zn-O films”. Journal of Non-crystalline
Solids 353 (2007) 956-958

18. S. R. Ovskinsky, “Reversible Electrical Switching
Phenomena in Disordered Structures”, Phys. Rev. Lett.
21, 1450(1968)

19. M. J. Rozenberg, I. H. Inoue, and M. J. Sanchez,
“Nonvolatile memory with multilevel switching: a basic
model”, Phys. Rev. Lett. 92, 178302(2004).

20. 王嗣裕, “Reliability and Processing Effects of
Bandgap Engineered SONOS (BE-SONOS) Flash Memory
Devices, 清華大學, 博士論文, 2008.

21. Marvin H. White, Dennis A. Adams, and Jiakang B “On
The Go with SONOS”. IEEE July 2000

22. Hirotaka Hamamura, Takeshi Ishida, Toshiyuki Mine,
Yutaka Okuyama, Digh Hisamoto, Yasuhiro Shimamoto,
Shin’ichiro Kimura and Kazuyoshi Torii “Electron
trapping characteristics and scalability of HfO2 as a
trapping layer in sonos-type flash memories.” IEEE
CFP08RPS-CDR 46th Annual International Reliability
Physics Symposium, Phoenix, 2008

23. Hee-Wook You and Won-Ju Cho “Charge trapping
properties of the HfO2 layer with various thickness for
charge trap flash memory applications”, Appl. Phys.
Lett. 96, 093506 2010

24. S. Tiwari, F. Rana, K. Chan, H. Hanafi W. Chan, and D.
Buchanan, “Volatile and Non-Volatile Memories in
Silicon with Nano-Crystal Storage”, IEDM Tech. Dig.,
521(1995).

25 S. Tiwari, F. Rana, H. Hanafi, A. Hartstein, E. F.
Crabbe, and K. Chan, “A silicon nanocrystals based
memory”, Appl. Phys. Lett. 68, 1377(1996).

26. M. Lenzlinger, E. H. Snow, “Fowler-Nordheim tunneling
in thermally grown SiO2”, J. Appl. Phys. 40, 278(1969).

27. L. L. Chang, P. J. Stiles, and L. Esaki, “Electron
tunneling between a metal and a semiconductor:
characteristics of Al-Al2O3-SnTe and –GeTe junctions”,
J. Appl. Phys. 38, 4440(1967).


28. K. F. Schuegraf, C. C. King, and C. Hu, “Ultra-thin
dioxide leakage current and scaling limit”, Symp. VLSI
Tech. Dig., IEEE, 18(1992).

29 T. Tuomi, M. Tuominen, E. Prieur, J. Lahtinen, and
Laakkonen, “Synchrotron section topographic study of
czochralski-grown silicon wafers for advanced memory
circuits”, J. Electronchem. Soc. 142, 1699(1995)

30. D. N. Kouvatsos, V. L. Sougleridis, and A. G.
Nassiopoulou, “Charging effects in silicon nanocrystals
within SiO2 layers, fabricated by chemical vapor
deposition, oxidation, and annealing ”, Appl. Phys.
Lett., 82, 397(2003).

31. L. W. Teo, W. K. Choi, W. K. Chim, V. Ho, C. M. Moey,
M. S. Tay, C. L. Heng, Y. Lei, D. A. Antoniadis, and E.
A. Fitzgerald, “Size control and charge storage
mechanism of germanium nanocrystals in a metal-
insulator-semiconductor structure”, Appl. Phys. Lett.
81, 3639(2002).

32. Y. Shi, K. Saito, H. Ishikuro, and T. Hiramoto,
“Effects of interface traps on charge retention
characteristics in silicon-quantum-dot-based metal-oxide-
semiconductor diodes”, J. J. Appl. Phys. 38, 425(1999)


33.Y. Shi, K. Saito, H. Ishikuro, and T. Hiramoto,
“Effects of traps on charge storage characteristics in
metal-oxide-semiconductor memory structures based on
silicon nanocrystals”, J. Appl. Phys. 84, 2358(1998).

34. G. Crisenza, C. Clementi, G. Ghidini, and M. Tosi,
“Floating gate memories reliability”, Quality and
Reliability International, 8, 177(1992).

35. J. Chen, T. Y .Chan, I. C. Chen, P. K. Ko, and C. Hu
“Subbreakdown drain Leakage current in MOSFET” IEEE
Electron Device Lett., vol. EDL-8, pp. 515-517. Nov.
1987.Cc

36. G. Verma, and N. Mielke, “Relability performance of
ETOX based Flash memories,” in Proc. IEEE IRPS 1988,
pp. 158-166

37. S. Haddad, C. Chang, B. Swaminathan, and J. Lien,
“Degradation due to hole trapping in flash memory
cells,” IEEE Electron Device Lett., vol. 10, pp. 117-
119, Mar. 1989.

38. Jong Jin Lee, Xuguang Wang, Weiping Bai, Nan Lu, and
Dim-Lee Kwong “Theoretical and Experimental
Investigation of Si Nanocrystal Memory Device With HfO2
High- Tunneling Dielectric”. IEEE Transactions on
Electron Devices, Vol. 50, No.10, October 2003.

39.Chen-Chan Wang, Yan-Kai Chiou, Che-Hao Chang, Jiun-Yi
Tseng, Lin-Jung Wu, Chun-Yu Chen and Tai-Bor Wu “Memory
characteristics of Au nanocrystal embedded in metal-
oxide-semiconductor structure by using atomic-layer-
deposited Al2O3 as control oxide” J.Phys. D: Appl.
Phys. 40 (2007) 1673-1677

40. Roberto Bez , Agostino Pirovano “Non-volatile memory
technologies: emerging concepts andnew materials” ,
Materials Science in Semiconductor Processing 7 (2004)
349–355

41. Hirotaka Hamamura, Takeshi Ishida, Toshiyuki Mine,
Yutaka Okuyama, Digh Hisamoto, Yasuhiro Shimamoto,
Shin’ichiro Kimura and Kazuyoshi Torii “Electron
trapping characteristics and scalability of HfO2 as a
trapping layer in SONOS-type flash memories” IEEE
46th Annual International Reliability Physics
Symposium, Phoenix, 2008

42. Cheng-Wei Cheng, Yuan-Chieh Tseng, Tai-Bor Wu, Li-Jen
Chou “Enhanced polarization switching characteristics
of Pb(Zr0.5Ti0.5)O3–Pt nanocomposite thin films” J.
Mater. Res., 19, 1043 (2004).

43. K. N. Tu, J. W. Mayer, and L. C. Feldman, “Electronic
thin film science”, NewYork: Macmillan, (1992).

44. Yun-Shan Lo, Ke-Chih Liu, Cheng-Wei Cheng, Jyun-Yi Wu,
Cheng-Hao Hou, and Tai-Bor Wu “Field enhancement
effect of nanocrystals in bandgap engineering of tunnel
oxide for nonvolatile memory application” Appl. Phys.
Lett.94, 082901 2009