當浮動閘極結構之快閃記憶體無法滿足元件微縮的發展時，SONOS-type是取代浮動閘極結構的熱門候選者之一。然而，以氮化矽為電荷儲存層之SONOS快閃記憶體發展到次微米以下時並無法再以降低穿隧氧化層的方式來提高寫入速度，且元件的電荷保存力也將面臨挑戰。而金屬氧化物有較小的能隙，可減少寫入時額外能障，故有較快的寫入特性，本論文即在探討以Hf-based的高介電材料當電荷儲存層並研究不同Hf/Al組成比的電荷儲存層對元件特性的影響。
由實驗結果可發現，以HfO2作為快閃記憶體之電荷儲層以500℃~600℃為最佳退火溫度。若以不同組成比的HfxAlyO堆疊作電荷儲存層，Al含量從穿隧氧化層到上氧化層以逐漸增加的組成有較佳的寫入/抹除特性。比較電容的不同製程以有隔離的結構特性較佳。HfO2添了Al2O3可提高熱穩定性外也提供較高的電荷缺陷密度來捕捉穿隧電荷並且保有適當的Si/HfxAlyO的能隙差，結果顯示，Hf/Al=1:2的HfxAlyO組成俱有較佳的寫入/抹除特性。另外HfxAlyO之電荷儲存層在元件可靠度方面也有很好的的電荷保存力和至少1000次耐讀寫能力，在100秒的抗汲極及讀取干擾方面，臨限電壓的漂移也不超過0.1V/0.2V。總結來說，HfxAlyO且Hf/Al=1:2的組成是適合當SONOS- type快閃記憶體的電荷儲存層的材料。

[1] Min She, “Semiconductor Flash Memory Scaling”, 2003
[2] Jing Hao Chen, et al., “Nonvolatile Flash Memory Device Using Ge Nanocrystals Embedded in HfAlO High-K Tunneling and Control Oxide:Device Fabrication and Electrical Performance”, IEEE Transactions on Electron Devices, Vol.51, No.11, NOVERMBER 2004
[3] Min She, et al., ”Impact of crystal size and tunnel dielectric on semiconductor nanocrystal memory performance”, IEEE Transactions on Electron Devices, Vol.50, No.9, SEPTEMBER 2003.
[4] Dong-Won Kim, et al., “Memory characterization of SiGe quantum dot flash memorieswith HfO2 and SiO2 tunneling dielectrics”, IEEE Transactions on Electron Devices, Vol.50, No.9, SEPTEMBER 2003.
[5] Marvin H. White, et al., ”On the go with SONOS”， IEEE CIRCUIT & DEVICE, JULY 2000.
[6] Marvin H. White, et al., “A low voltage SONOS nonvolatile semiconductor memory technology”, IEEE Transactions on Components, Packaging, and Manufacturing Technology, Vol.20, No.2, JUNE 1997.
[7] Jiankang Bu, et al., “Retention reliability enhanced SONOS NVSM with scaled programming voltage”, IEEE Aerospace Conference paper, Vol.5, P5-2383 5-2390,2001
[8] W. J. Tsai, et al., “Data retention behavior of a SONOS type two-bit storage flash memory cell”, IEEE International Electron Devices Meeting, 2001
[9] K. Tamer San, et al., “Effects of erase source bias on Flash EPROM device reliability”, IEEE Transactions on Electron Devices , Vol.42, No.1, JANUARY 1995
[10] 薛富元, “由模擬來探討Floating Gate Memory及SONOS元件微小化之極限”, 國立清華大學電子工程研究所, P6,2004
[11] Jan Van Houdt, et al., “High-k materials for nonvolatile memory applications” ,IEEE Physics Symposium, 2005.
[12] T. Sugizaki, et al., “Novel multi-bit SONOS type flash memory using a high-k charge trapping layer”, IEEE Symposium on VLSI Technology Digest of Technical Paper, 2003.
[13] Xuguang Wang, et al., ”A novel MONOS-type nonvolatile memory using high-k dielectrics for improved data retention and programming speed”, IEEE Transactions on Electron Device, Vol.51, No.4, APRIL, 2004.
[14] Kuo-Hong Wu, et al., ”SONOS device with tapered bandgap nitride layer”, IEEE Transactions on Electron Device, 2005.
[15] Yan-Ny Tan, et al., ”Over-erase phenomenon in SONOS-type flash memory and its minimization using a hafnium oxide charge storage Layer”, IEEE Transactions on Electron Device ,Vol.51, No.7,JULY, 2004.
[16] Yan-Ny Tan, et al., ”High-k HfAlO charge trapping layer in SONOS-type nonvolatile memory device for high speed operation”, IEEE Electron Device Meeting, p889-892, 2004.
[17] M. Specht, et al., ”Retention time of novel charge trapping memories using Al2O3 dielectrics”, IEEE Symposium on VLSI, 2003.
[18] Sanghum Jeon, et al., ”Triple high k stacks (Al2O3-HfO2-Al2O3) with high pressure (10atm) H2 and D2 annealing for SONOS type flash memory device applications”, IEEE Conference on Nanotechnology, 2004.
[19] Xuguang Wang, et al., ” A novel high-k SONOS memory using TaN Al2O3/Ta2O5 /HfO2 Si structure for fast speed and long retention operation”, IEEE Transactions on Electron Device, Vol.53, No.1, JANUARY, 2006.
[20] M. Specht, et al., ”Charge trapping memory structures with Al2O3 trapping dielectric for high-temperature applications”, Solid State Electronics, 2005.
[21] Hiroshi Aozasa, et al., ”Analysis of Carrier Traps in Si3N4 in Oxide Nitride Oxide for Metal Oxide Nitride Oxide Silicon Nonvolatile Memory”, J, Appl. Pyhs, Vol.38, p.1441-1447, 1999.
[22] Min She, et al., ”Silicon-nitride as a tunnel dielectric for improved SONOS-type flash memory”, IEEE Electron Device Letters, Vol.24, No.5, MAY, 2003.
[23] Hang-Ting Lue, et al., ”BE-SONOS A bandgap engineered SONOS with excellent performance and reliability”, IEEE International Electron Devices Meeting, 2005.
[24] B. Govoreanu, et al., “VARIOT:A Novel Multilayer Tunnel Barrier Concept for Low-Voltage Nonvolatile Memory Devices”, IEEE Electron Devices Letter, Vol.24, No.2, p99-101, FEBRUARY 2003.
[25] 王炳琨，”不同HfOxNy/SiO2堆疊穿隧介電層對快閃記憶體操作特性之影響”，國立清華大學工程與系統科學研究所，p60-p94, 2004.
[26] Steve S, Chung, et al., ”A novel leakage current separation technique in a direct tunneling regime gate oxide SONOS memory cell”, IEEE International Electron Devices Meeting, 2003.
[27] H. Reisinger, et al., “A Novel SONOS Structure For Nonvolatile Memories With Improved Data Retention”, IEEE Symposium on VLSI Technology Digest of Technical Paper, 1997
[28] Sanghun Jeon, et al., ”High Work-Function metal gate and high-K dielectric for charge trap flash memory device applications”, IEEE Transactions on Electron Device, Vol.52, No.12, DECEMBER 2005.
[29] James A, et al., ”Charge trapping and annealing in high-k gate dielectrics”, IEEE Transactions on Nuclear Science, Vol.51, No.6, DECEMBER 2004.
[30] Chang Hyun Lee, et al., ”A novel SONOS structure of SiO2-SiN-Al2O3 with TaN metal gate for multi-giga bit flash memories”, IEEE International Electron Devices Meeting, 2003.
[31] W. J. Zhu, et al., ”Effect of Al Inclusion in HfO2 on the Physical and electrical properties of the dielectrics”, IEEE Electron Electron Device Letters, Vol.23, No.11, NOVEMBER 2003.
[32] J. Petry, et al., ”The band structure of ALCVD AlZr and AlHf oxides as measured by XPS”, Materials Science and Engineering, 2004.
[33] H. Y. Yu, et al., ”ALD (HfO2)x(Al2O3)1-x high-k gate dielectrics for advanced MOS devices application”, Thin Solid Films, 2004.
[34] Moon Sig Joo, et al., ”Formation of hafnium-aluminum-oxide gate dielectric using single cocktail liquid source in MOCVD process”, IEEE Transactions on Electron Device, Vol.50, No.10, OCTOBER 2003.
[35] Moon Sig Joo, et al., ”Dependence of Chemical Composition Ratio on Electrical Properties of HfO2-Al2O3 Gate Dielectric”, Jpn. J. Appl. Phys., No.3A, Pl220-l222, MARCH 2003.
[36] Hei Wong, ”Thermal stability and electronic structure of hafnium and zirconium oxide films for nanoscale MOS device applications”, Proceedings of the Fifth IEEE International Caracas Conference on Devices, Circuits and Systems, NOVEMBER 2003.
[37] Verma, et al., ”Reliability Performance of ETOX Based Flash Memory”, International Reliability Physics Symp, P.158, 1998.
[38] Haddad, et al., ”Degradation Due to Hole Trapping in Flash Memory Cells”, IEEE Electron Dev. Lett., Vol.10, No3, P.117, Mar. 1989.
[39] Adam Brand, et al., ”Novel Read Distub Failure Mechanism Induced by Flash Cycling”, International Reliability Physics Symp., P.127, 1993.
[40] 張俊彥，鄭晃忠,”積體電路製程及設備技術手冊”，中華民國電子材料與元件協會，p188,1997.