Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Yuji Koga.
ION IMPLANTATION TECHNOLOGY: 16th International Conference on Ion Implantation Technology - IIT 2006 | 2006
Shigeki Sakai; Masayasu Tanjyo; Nariaki Hamamoto; Sei Umisedo; Tomoaki Kobayashi; Takatoshi Yamashita; Takao Matsumoto; Tadashi Ikejiri; Kohei Tanaka; Yuji Koga; Satoru Yuasa; Masao Naito; Nobuo Nagai
A new medium current ion implanter has been developed based on the EXCEED3000, which is highly reliable and widely used in 300mm fabs. The ion implanter now has to be designed so that it can precisely measure and control beam characteristics. For example beam angles have to be controlled in halo implantation because high tilt angle implantation is done according to the device geometric structure. Not only horizontal beam profile system but also vertical beam profile system are implemented in EXCEED3000AH‐G3 for the precise implantation control.
international workshop on junction technology | 2010
Tsutomu Nagayama; Hiroshi Onoda; Masayasu Tanjyo; Nariaki Hamamoto; Sei Umisedo; Yuji Koga; Noriaki Maehara; Yasunori Kawamura; Yoshiki Nakashima; Yoshikazu Hashino; Masahiro Hashimoto; Hideki Yoshimi; Shinichi Sezaki; Nobuo Nagai
Phosphorus transient enhanced diffusion (TED) is caused by interstitial diffusion mechanism. It is important for the efficient suppression of phosphorus diffusion that some carbons could be located on lattice point in the initial stage of re-growth during annealing and trap interstitial Silicon. Carbon co-implantation after Germanium, pre-amorphization implantation (PAI) is applied for the applications of n+/p junction formation and the effects of Carbon co-implantation are reported. In our experiments it is shown that suppression of Phosphorus diffusion could be achieved with conventional rapid thermal annealing (RTA) by using cluster Carbon (C16Hx+, C7Hx+) co-implantation for the self-amrphization. Our experimental data suggests that cluster carbon co-implantation enable to suppress phosphorus diffusion without germanium pre-amorphous implantation. In this paper the characteristics of cluster Carbon co-implantation after RTA are introduced from experimental results which were obtained by secondary ion mass spectroscopy (SIMS) measurement, transmission electron microscopy (TEM) and sheet-resistance measurement.
ISTC/CSTIC 2009 (CISTC) | 2009
Masayasu Tanjyo; Nariaki Hamamoto; Tsutomu Nagayama; Sei Umisedo; Yuji Koga; Noriaki Maehara; Hideyasu Une; Takao Matsumoto; Nobuo Nagai; John Borland
Newly developed sweep beam Cluster ion implanter: CLARIS with 0.2-7keV energy range for Boron beam and 1-10keV energy range for Carbon beam is introduced. Novel Cluster ion implantation technology is capable for 45nm beyond device requiring USJ formation ( 70%) and low sheet resistivity (<1200Ω/sq). Comparison of retain dose and sheet resistivity of B18, BF2, and B beams with FLA shows the superiority of the B18 implantation for less than 500eV implantation.
international workshop on junction technology | 2007
Nariaki Hamamoto; Sei Umisedo; Yuji Koga; Takao Matsumoto; Tsutomu Nagayama; Masayasu Tanjyo; Nobuo Nagai; Tom Horsky; Dale C. Jacobson; Hilton F. Glavish
New boron cluster ion implanter is being developed with using alpha-type equipment. High through-put at ultra low energy region in drift mode with good implantation qualities is confirmed and presented. We continue to develop this cluster ion implantation technology for mass production.
international workshop on junction technology | 2010
Masayasu Tanjyo; Nariaki Hamamoto; Sei Umisedo; Yuji Koga; Hideyasu Une; Noriaki Maehara; Yasunori Kawamura; Yoshikazu Hashino; Yoshiki Nakashima; Masahiro Hashimoto; Tsutomu Nagayama; Hiroshi Onoda; Nobuo Nagai; Tom Horsky; Sami K. Hahto; Dale C. Jacobson
The cluster ion beam implanter named CLARIS has been developed for beyond 45nm device production use, which is characterized by the high productivity, high effective low energy high current, and preciseness of incident beam angle and dose uniformity. For the USJ process application, a cluster beam co-implantation is introduced. Carbon cluster co-implantation and the boron cluster beam implantation productivity are evaluated from a COO and CoC view point and compared with the conventional high current implanter.
international conference on advanced thermal processing of semiconductors | 2010
Hiroshi Onoda; Nariaki Hamamoto; Tsutomu Nagayama; Shigeki Sakai; Masayasu Tanjyo; Sei Umisedo; Yuji Koga; Noriaki Maehara; Yasunori Kawamura; Yoshiki Nakashima; Kouhei Tanaka; Yoshikazu Hashino; Masahiro Hashimoto; Hideki Yoshimi; Shinichi Sezaki; Jason Reyes; S. Prussin
Cluster C implantation at low temperature has been studied in terms of amorphous Si (a-Si) formation and elimination of B implanted induced end of range defects (EORDs). Thickness of a-Si can be controlled by C equivalent energy and dose. Monomer C never creates a-Si layer at less than 1E15/ cm<sup>2</sup> at 25°C implant. Dose increase and temperature decrease starts to create a-Si layer. On the other hand, cluster C7 implant creates a-Si layer at less than 5E14/cm<sup>2</sup> dose even at 25°C, and −30°C implant increases the a-Si thickness by around 7∼8nm in each C dose. A large amount of EORDs remain in cluster B10 25°C implant sample after RTA at 950°C. The situation does not change a lot with B10 −30°C implant. On the other hand, cluster C7 co-implant with B10 at 25°C, however, greatly reduces EORD density. EORD free can be realized in C7 co-implant with B10 at −30°C. Cluster C7 co-implant at −30°C assists the EORD elimination. Sheet resistance of cluster C and B10 co-implanted at −30°C sample is remarkably low compared with only B10 implanted sample. It can be concluded that cluster C implantation at −30°C is very effective for eliminating EORDs and obtaining high carrier activation.
international workshop on junction technology | 2012
Yoshiki Nakashima; Nariaki Hamamoto; Tsutomu Nagayama; Yuji Koga; Sei Umisedo; Masahiro Hashimoto; Hiroshi Onoda
Low temperature cluster carbon co-implantation was applied for phosphorous activation enhancement and transient enhanced diffusion (TED) suppression. The dependence of phosphorous activation and TED on 1) carbon energy, 2) dose and 3) substrate temperature have been investigated. 1) Implanted carbon depth compared with phosphorous depth was optimized for better phosphorous TED suppression and phosphorous activation. 2) Junction depth and sheet resistance (Rs) were evaluated as a function of carbon dose. 3) Amorphous layer thickness was controlled by cooling down the substrate temperature and the influence on TED and activation was evaluated. Finally shallow junction with low Rs has been achieved using low temperature cluster carbon co-implantation.
international workshop on junction technology | 2012
Karuppanan Sekar; Nobuhiro Tokoro; Hiroshi Onoda; Yoshiki Nakashima; Yuji Koga; Nariaki Hamamoto; Tsutomu Nagayama; Joshua Herman; Steve Novak; Martin Rodgers; Daniel Franca; Saikumar Vivekanand
For 28nm and beyond technology nodes it is essential to enhance carrier mobility of the devices by introducing embedded Si:C structures using new materials or structures or new implant and anneal process schemes. In this article we review and verify available information using Si:C formation through implant and anneal approach with low temperature cluster carbon and cluster phosphorous implants. We show here the difference in process results for single and double carbon implants for various pre-anneal and laser annealing conditions. This article explores the effect of cluster carbon implants on various pre-anneal conditions and implant temperature effects on sheet resistance, carbon substitution and junction depths which are critical in determining important device characteristics.
ION IMPLANTATION TECHNOLOGY 2012: Proceedings of the 19th International Conference on Ion Implantation Technology | 2012
Karuppanan Sekar; Nobuhiro Tokoro; Hiroshi Onoda; Yoshiki Nakashima; Yuji Koga; Nariaki Hamamoto; Tsutomu Nagayama; Joshua Herman; Steve Novak; Martin Rodgers; Daniel Franca; Saikumar Vivekanand
It is shown that Cluster Carbon implantation can be an effective process for making Si:C stressor layer, particularly due to the self-amorphization feature of cluster implantation. Carbon incorporation challenges the formation of NMOS junction structures due to the competition between carbon and dopant atoms to occupy the Si lattice sites and also excess carbon causes serious deactivation of the dopant species. This work now extends to show the effect of low temperature multiple carbon implants and laser annealing on sheet resistance (Rs), carbon substituitionality ([C]subs) and re-crystallization of Si:C layer. The results show that sheet resistance is lower for room temperature implants when compared to cold implants for any anneal condition and but the carbon substitution is slightly higher at low temperature cases. Good recrystallization with no visible defects as seen through XTEM images were observed for both RT and cold implant cases for spike annealed cases. For low temperature RTA anneals, cold i...
ION IMPLANTATION TECHNOLOGY 2012: Proceedings of the 19th International Conference on Ion Implantation Technology | 2012
Yoshiki Nakashima; Nariaki Hamamoto; Tsutomu Nagayama; Yuji Koga; Sei Umisedo; Yasunori Kawamura; Masahiro Hashimoto; Hiroshi Onoda
Carbon co-implantation is well known as an effective method for suppressing boron/phosphorous transient enhanced diffusion (TED). Germanium pre-amorphization implantation (PAI) is usually applied prior to carbon co-implantation for suppressing channeling tail of dopants. In this study, cluster carbon was applied instead of the combination of germanium PAI and monomer carbon co-implantation prior to phosphorous implantation. Dependence of phosphorous activation and TED on amorphous layer thickness, carbon dose, carbon distribution and substrate temperature have been investigated. Cluster carbon implantation enables thick amorphous layer formation and TED suppression at the same time and low temperature implantation enhances the ability of amorphous layer formation so that shallow junction and low Rs can be achieved without Ge implantation.
Collaboration
Dive into the Yuji Koga's collaboration.
National Institute of Advanced Industrial Science and Technology
View shared research outputs