Approaching Defect-free Amorphous Silicon Nitride by Plasma-assisted Atomic Beam Deposition for High Performance Gate Dielectric.
In the past few decades, gate insulators with a high dielectric constant (high-k dielectric) enabling a physically thick but dielectrically thin insulating layer, have been used to replace traditional SiOx insulator and to ensure continuous downscaling of Si-based transistor technology. However, due to the non-silicon derivative natures of the high-k metal oxides, transport properties in these dielectrics are still limited by various structural defects on the hetero-interfaces and inside the dielectrics. Here, we show that another insulating silicon compound, amorphous silicon nitride (a-Si3N4), is a promising candidate of effective electrical insulator for use as a high-k dielectric. We have examined a-Si3N4 deposited using the plasma-assisted atomic beam deposition (PA-ABD) technique in an ultra-high vacuum (UHV) environment and demonstrated the absence of defect-related luminescence; it was also found that the electronic structure across the a-Si3N4/Si heterojunction approaches the intrinsic limit, which exhibits large band gap energy and valence band offset. We demonstrate that charge transport properties in the metal/a-Si3N4/Si (MNS) structures approach defect-free limits with a large breakdown field and a low leakage current. Using PA-ABD, our results suggest a general strategy to markedly improve the performance of gate dielectric using a nearly defect-free insulator.
Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 70101, Taiwan.
Shu-Ju
SJ
Tsai
Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
Chiang-Lun
CL
Wang
Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
Hung-Chun
HC
Lee
Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
Chun-Yeh
CY
Lin
Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
Jhih-Wei
JW
Chen
National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
Hong-Wei
HW
Shiu
National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
Lo-Yueh
LY
Chang
National Nano Devices Laboratories, National Applied Research Laboratories, Tainan 741, Taiwan.
Han-Ting
HT
Hsueh
Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan.
Hung-Ying
HY
Chen
Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
Jyun-Yu
JY
Tsai
Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
Ying-Hsin
YH
Lu
Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
Ting-Chang
TC
Chang
Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
Li-Wei
LW
Tu
Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
Hsisheng
H
Teng
Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
Yi-Chun
YC
Chen
National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
Chia-Hao
CH
Chen
Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan.
Chung-Lin
CL
Wu