Browsing by Author "Su, HP"

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Excellent emission characteristics of tunneling oxides formed using ultrathin silicon films for flash memory devices
(1996-06-01)
Wang, PW
;
Ku, TK
;
Su, HP
;
Hong, G
;
Cheng, HC
A novel technique using oxidized ultrathin rugged polysilicon films on silicon substrates has been appied to significantly improve the tunneling efficiency of thin oxides. As compared with oxidized amorphous silicon films, these rugged polysilicon films can achieve a higher emission current. High-resolution transmission electron microscopy (HRTEM) was used to observe the atomic-scale microtips at the SiO2/Si and polysilicon/SiO2 interfaces. According to the extracted geometry parameters of the microtips, a two-dimensional numerical simulator based on the finite difference method using the curved emitting surface of microtips can well explain the remarkable current asymmetry of the dielectrics. This suggests that the oxidized rugged polysilicon films can form higher microtips and smaller tip angles, resulting in better emission characteristics that will enable potential applications to future 5-V-only nonvolatile memories.
The oxidation mechanism of low-pressure dry oxidation of nitrides for memory devices
(1997-09-01)
Liu, HW
;
Su, HP
;
Lai, WK
;
Cheng, HC
;
電子工程學系及電子研究所
To be utilized in the high density dynamic random access memory devices, low-pressure dry oxidation of the very thin nitrides has been performed to successfully obtain the ultrathin capacitors' dielectrics with the effective oxide thickness (t(ox,eff)) of 30 - 60 Angstrom. For the electrical properties, the low-pressure dry oxidized (LPDO) nitrides express thinner effective oxide thickness, lower leakage current, and higher reliability than do the atmospheric pressure dry oxidized (APDO) nitrides. After analyzing the diluted HF etching profiles, Auger electron spectrum and Fourier transform infrared spectrum data, an oxide/nitride/oxide (O/N/O) structure is realized for the LPDO samples with respect to the nitride/oxide structure for the APDO ones. This ultrathin O/N/O structure is believed to be the main cause of improving the electrical characteristics. Finally, a low-pressure enhanced oxidation model is also proposed to explain the unusual oxidation phenomenon on the top of the nitride films. The mechanisms of APDO and atmospheric pressure wet oxidation of nitride films are also compared.
The oxidation mechanism of low-pressure dry oxidation of nitrides for memory devices
(1997-09-01)
Liu, HW
;
Su, HP
;
Lai, WK
;
Cheng, HC
;
電子工程學系及電子研究所
To be utilized in the high density dynamic random access memory devices, low-pressure dry oxidation of the very thin nitrides has been performed to successfully obtain the ultrathin capacitors' dielectrics with the effective oxide thickness (t(ox,eff)) of 30 - 60 Angstrom. For the electrical properties, the low-pressure dry oxidized (LPDO) nitrides express thinner effective oxide thickness, lower leakage current, and higher reliability than do the atmospheric pressure dry oxidized (APDO) nitrides. After analyzing the diluted HF etching profiles, Auger electron spectrum and Fourier transform infrared spectrum data, an oxide/nitride/oxide (O/N/O) structure is realized for the LPDO samples with respect to the nitride/oxide structure for the APDO ones. This ultrathin O/N/O structure is believed to be the main cause of improving the electrical characteristics. Finally, a low-pressure enhanced oxidation model is also proposed to explain the unusual oxidation phenomenon on the top of the nitride films. The mechanisms of APDO and atmospheric pressure wet oxidation of nitride films are also compared.