An Advanced Fabrication Technology of Hemispherical Grained (HSG) Poly-Si for High Capacitance Storage Electrodes

Watanabe, Heiji; Tatsumi, Takahide; Niino, Toshiki; Sakai, A.; Adachi, S.; Aoto, Nahomi; Koyama, Kyouhei; Kikkawa, Takahiro

doi:10.7567/ssdm.1991.a-8-4

Cited by 2 publications

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“…The density of the hemispherical grains on the surface increases with increasing in situ annealing temperature and time. This result is in agreement with the results of Watanabe et al [11] and Sakai et al [15] obtained by using the ultra-high vacuum annealing of the amorphous film after removing a native oxide. They observed that the hemispherical grains are formed on the amorphous silicon surface and protrude from the original amorphous silicon plane.…”

Section: Resultssupporting

confidence: 93%

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A study of the morphology and microstructure of LPCVD polysilicon

Lee

Rha

1993

J Mater Sci

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The morphology and microstructure of polysilicon films deposited by low-pressure chemical vapour deposition (LPCVD) have been investigated as a function of deposition conditions. The deposition temperature was varied from 540-640 ~ As-deposited polysilicon films had a rough surface with (1 1 0) textured columnar grain structure, while as-deposited amorphous films had a smooth surface. The polysilicon film deposited at the amorphous to polycrystalline transition temperature had an extra-rough, rugged surface with (31 1 ) texture. At the transition temperature, the grain structure tended to shift from the polycrystalline to the amorphous state with increasing deposition pressure and film thickness. It was found that nucleation of amorphous film during in situ annealing at the transition temperature without breaking the vacuum began to occur from surface silicon atom migration, in contrast to a heterogeneous nucleation during film deposition.

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Section: Resultssupporting

confidence: 93%

“…However, in order to obtain the sufficient storage capacitance required for 64M bit dynamic random access memory (DRAM) and beyond, some fabrication technologies having an uneven surface of hemispherically grained (HSG) polysilicon film have been suggested for increasing effective surface area [10,11].…”

Section: Introductionmentioning

confidence: 99%

A study of the morphology and microstructure of LPCVD polysilicon

Lee

Rha

1993

J Mater Sci

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“…11,12 Thus, the cleanliness of Si surface has been emphasized for a successful HSG Si process. 4,7 Figure 8 shows the normalized capacitance of cell capacitor referenced to a control wafer without O 3 exposure. The capacitance of cell capacitor decreased to 84% of the reference wafer after 20 min of exposure at 20 ppb.…”

Section: Resultsmentioning

confidence: 99%

“…2,3 The growth of HSG Si can be performed either by low pressure chemical vapor deposition ͑LPCVD͒ or by annealing native-oxide-free amorphous silicon under high vacuum systems. 4,5 Another method to improve the growth of HSG Si and enhance the corresponding surface area of the bottom electrode is the seeding method which uses Si molecular beam deposition and subsequent annealing. [5][6][7] It is known that in the growing of HSG Si on amorphous silicon film, the diffusive silicon atom migrates to the microcrystal by the thermal annealing after seeding with SiH 4 or Si 2 H 6 .…”

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confidence: 99%

“…Though Mansoori 7 proposed that the density and grain size of HSG Si could be controlled by deposition and anneal time, the existence of native oxide suppresses migration of silicon atoms on the surface of the bottom electrode and causes poor density or/and small grain size of HSG Si. 4,7 It is well known that the ambient moisture and oxygen affect the growth of native oxide on the surface of amorphous silicon. Thus, it is emphasized that the clean surface of amorphous silicon is needed to grow HSG Si.…”

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Environmental Ozone Effect on the Growth of Hemispherical Grained Silicon for ULSI DRAM Stacked Capacitor

Park¹,

Kim²,

Kim³

et al. 2001

J. Electrochem. Soc.

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Hemispherical grained silicon ͑HSG Si͒ is a state-of-the-art method used to increase the surface area of the bottom electrode in an ultralarge-scale integration dynamic random access memory ͑ULSI DRAM͒ stacked capacitor. Since contaminants affect the formation and growth of HSG Si, the control of surface cleanliness on amorphous Si of the bottom electrode is crucial. The most critical contaminant is native oxide which forms when amorphous Si surface of the bottom electrode is exposed to air. Native oxide growth is mainly influenced by airborne ozone (O 3 ). In this work, it is shown that the native oxide grows linearly with exposure time to O 3 . Also we show that there is a high growth rate of native oxide at a high concentration of O 3 , and that HSG-Si formation in O 3 is related to crystalline quality, morphology, and reflectivity. Electrical characteristics of HSG Si are evaluated with respective O 3 conditions and a variation of capacitance is observed. Additionally, an in situ precleaning process followed by the growth of HSG Si under vacuum and implementation of O 3 chemical filters are proposed in order to control O 3 .

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An Advanced Fabrication Technology of Hemispherical Grained (HSG) Poly-Si for High Capacitance Storage Electrodes

Cited by 2 publications

References 0 publications

A study of the morphology and microstructure of LPCVD polysilicon

A study of the morphology and microstructure of LPCVD polysilicon

Environmental Ozone Effect on the Growth of Hemispherical Grained Silicon for ULSI DRAM Stacked Capacitor

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