Farklı kapı oksitli RadFET dozimetrelerinin ışınlama öncesi elektriksel karakteristiklerinin TCAD benzetim programı ile değerlendirilmesi

Yıl 2017, Cilt: 21 Sayı: 6, 1258 - 1265, 01.12.2017

Ayşegül Kahraman Ercan Yılmaz

https://doi.org/10.16984/saufenbilder.337279

Öz

Bu çalışmanın amacı, kapı oksiti
yüksek-k’lı dielektriklerden oluşan RadFET dozimetrelerinin ışınlama öncesi
eşik gerilimlerini belirlemek ve sonuçları, kapı oksiti SiO₂’den
oluşan geleneksel sensörlerle kıyaslamaktır. Ayrıca çalışmada, farklı
konsantrasyonlu, derinlikli ve genişlikli p⁺ bölgelerinin
RadFET’lerin elektriksel karakteristiği üzerine etkileri de incelenmiştir. Bu
amaçla, dozimetrelerin duyar bölgeleri olarak 400 nm kalınlığında yüksek-k’lı
Al₂O₃, HfO₂ dielektrikleri ve SiO₂
kullanılmıştır. Sensörler, Silvaco TCAD benzetim programında tasarlanmıştır. p⁺
bölgelerinin uzunlukları, I_d-V_g karakteristiğini
değiştirirken, bu bölgelerin derinlikleri ve belirli bir değere kadar
konsantrasyonları elektriksel karakteristikte önemli bir rol oynamamıştır. SiO₂,
Al₂O₃ ve HfO₂-RadFET’lerden elde edilen en
düşük eşik voltajları sırasıyla, -5.22, -3.63 ve -3.10 V olarak bulunmuştur. Bu
sonuçlar, yüksek-k dielektrikli RadFET’lerin, radyasyon testlerinin yapılması
koşuluyla, daha geniş ölçülebilir doz aralığı açısından yeni nesil dozimetreler
için gelecek vaat eden bir aday olduğunu göstermektedir.

Anahtar Kelimeler

RADFET, TCAD, Yüksek-k, Eşik voltajı

Evaluation of the pre-irradiation electrical characteristics of the RadFET dosimeters with diverse gate oxides by TCAD simulation program

Öz

The aim of the present study is to
determine the pre-irradiation threshold voltages of the RadFET dosimeters with
gate oxide composed of high-k dielectrics and compare the results with the
traditional sensors, the gate oxide of which is composed of SiO₂.
The effects of the p⁺ regions with different concentration, depth
and length on the electrical characteristic of the RadFETs were also
investigated in the study. For these purposes, Al₂O₃, HfO₂
high-k dielectrics and SiO₂ with the thicknesses of 400 nm were used
as the sensitive regions of the dosimeters. The sensors were designed in the
Silvaco TCAD simulation program. While the lengths of the p⁺ regions
changed the I_d-V_g characteristics of the RADFETs, the
depths and concentrations until a certain value of these regions did not play
an important role in electrical characteristic. The lowest threshold voltages
obtained from the SiO₂, Al₂O₃ and HfO₂-RadFETs
were found to be -5.22, -3.63, and -3.10 V, respectively. These results
demonstrated that RadFETs with high-k dielectrics may be promising candidate
for the new generated dosimeters in terms of broader measurable dose range
providing their radiation tests. 

Anahtar Kelimeler

RADFET, TCAD, High-k, Threshold voltage

Kaynakça

• M.A. Carvajal, S. García-Pareja, D. Guirado, M. Vilches, M. Anguiano, A.J. Palma, A.M. Lallena, “Monte Carlo simulation using the PENELOPE code with an ant colony algorithm to study MOSFET detectors,” Phys. Med. Biol., vol. 54, pp. 6263-6276, Oct. 2009. J.O. Goldsten, R.H. Maurer, P.N. Peplowski, A.G. Holmes-Siedle, C.C. Herrmann, B.H. Mauk, “The engineering radiation monitor for the radiation belt storm probes mission,” Space Sci. Rev., vol. 179, pp. 485-502, Nov. 2013. F. Ravotti, M. Glaser, A.B. Rosenfeld, M.L.F. Lerch, A.G. Holmes-Siedle, G. Sarrabayrouse, “Radiation monitoring in mixed environments at CERN: from the IRRAD6 facility to the LHC experiments,” IEEE T. Nucl. Sci., Vol. 54, pp. 1170-1177, Aug. 2007. A. Holmes-Siedle, L. Adams, “RadFET-A review of the use of metal-oxide silicon devices as integrating dosimeters,” Radiat. Phys. Chem., vol. 28, 235-244, 1986. G. Ristić, S. Golubović, M. Pejović, “Sensitivity and fading of pMOS dosimeters with thick gate oxide,” Sensor. Actuat. A-Phys., vol. 51, pp. 153-158, Nov. 1995. M.S. Martínez-García, J. Torres del Río, A.J. Palma, A.M. Lallena, A. Jaksic, “Comparative study of MOSFET response to photon and electron beams in reference conditions,” Sensor. Actuat. A-Phys., vol. 225, pp. 95-102, Apr. 2015. E. Yilmaz, İ. Doğan, R. Turan, “Use of Al2O3 layer as a dielectric in MOS based radiation sensors fabricated on a Si substrate,” Nucl. Instrum. Meth. A, vol. 266, pp. 4896-4898, Nov. 2008. A. Jaksic, G. Ristic, M. Pejovic, A. Mohammadzadeh, W. Lane, “Characterisation of radiation response of 400 nm implanted gate oxide RADETs,” Proc. 23rd International Conference on Microelectronics (MIEL 2002), 2002, pp. 727-730. A. Kahraman, E. Yilmaz, S. Kaya, A. Aktag, “Effects of packaging materials on the sensitivity of RadFET with HfO2 gate dielectric for electron and photon sources,” Radiat. Eff. Defect. S., vol. 170, pp. 832-844, Oct. 2015. M. Wind, P. Beck, A. Jaksic, “Investigation of the energy response of RADFET for high energy photons, electrons, protons, and neutrons,” IEEE T. Nucl. Sci., Vol. 56, pp. 3387-3392, Dec. 2009. A. Haran, A. Jakšić, N. Refaeli, A. Eliyahu, D. David, J. Barak, “Temperature effects and long term fading of implanted and unimplanted gate oxide RadFETs”, IEEE T. Nucl. Sci., vol. 51, pp. 2917-2921, Oct. 2004. G.S. Ristíc, N.D. Vasović, M. Kovačević, A.B. Jakšić, “The sensitivity of 100 nm RADFETs with zero gate bias up to dose of 230 Gy(Si),” Nucl. Instrum. Meth. B, vol. 269, pp. 2703-2708, Dec. 2011. G.S. Ristíc, M. Andjelković, A.B. Jakšić, “The behavior of fixed and switching oxide traps of RADFETs during irradiation up to high absorbed doses,” Appl. Radiat. Isotopes, vol. 102, pp. 29-34, Aug. 2015. S. Wang, P. Liu, J. Zhang, “Simulation of threshold voltage adjustment by B+ implantation for pMOS-RADFET application,” Proc. 8th IEEE International Conference on Nano/Micro Engineered and Molecular Systems (NEMS), 2013, pp. 262-263. C. Andersson, C. Rossel, M. Sousa, D.J. Webb, C. Marchiori, D. Caimi, H. Siegwart, Y. Panayiotatos, A. Dimoulas, J. Fompeyrine, “Lanthanum germanate as dielectric for scaled germanium metal-oxide-semiconductor device,” Microelectron. Eng., vol. 86, pp. 1635-1637, Jul.-Sep. 2009. W. Zhu, J-P. Han, T.P. Ma, “Mobility measurement and degradation mechanisms of MOSFETs made with ultrathin high-k dielectrics”, IEEE T. Electron Dev., vol. 51, pp. 98-105, Jan. 2004. H. Wang, Y. Wang, J. Wang, C. Ye, H.B. Wang, J. Feng, B.Y. Wang, Q. Li, Y. Jiang, “Interface control and leakage current conduction mechanism in HfO2 film prepared by pulsed laser deposition,” Appl. Phys. Lett., vol. 93, pp. 202904-1-3, Nov. 2008. A. Kahraman, E. Yilmaz, S. Kaya, A. Aktag, “Effects of post deposition annealing, interface states and series resistance on electrical characteristics of HfO2 MOS capacitors”, J. Mater. Sci.: Mater. Electron., 26, pp. 8277-8284, Nov. 2015. F.B. Ergin, R. Turan, S.T. Shishiyanu, E. Yilmaz, “Effect of γ-radiation on HfO2 based MOS capacitor,” ,” Nucl. Instrum. Meth. B, vol. 268, pp. 1482–1485, May 2010. S. Kaya, E. Yilmaz, “Influences of Co-60 gamma-ray irradiation on electrical characteristics of Al2O3 MOS capacitors,” J. Radioanal. Nucl. Ch., vol. 302, pp. 425-431, Oct. 2014. S. Kaya, E. Yilmaz, A. Kahraman, H. Karacali, “Frequency dependent gamma-ray irradiation response of Sm2O3 MOS capacitors,” Nucl. Instrum. Meth. B,vol. 358, pp. 188-193, Sep. 2015. A. Kahraman, E. Yilmaz, A. Aktag, S. Kaya, “Evaluation of radiation sensor aspects of Er2O3 MOS capacitors under zero gate bias,” IEEE T. Nucl. Sci., Vol. 63, pp. 1284-1293, Apr. 2016. P.M. Tirmali, A.G. Khairnar, B.N. Joshi, A.M. Mahajan, “Structural and electrical characteristics of RF-sputtered HfO2 high-k based MOS capacitors,” Solid State Electron., 62, pp. 44-47, Aug. 2011. J. Robertson, “High dielectric constant oxides,” Eur. Phys. J. Appl. Phys., vol. 28, pp. 265-291, Dec. 2004. A.L.S. Loke, Z-Y. Wu, R. Moallemi, C.D. Cabler, C.O. Lackey, T.T. Wee, B.A. Doybe, “Constant-Current threshold voltage extraction in HSPICE for nanoscale CMOS analog design,” Advanced Micro Devices, Inc., 1-19. Silvaco. (2008, Apr.). ATHENA User’s Manual. Silvaco. Santa Clara, CA. [Online]. Available: http://perso.esiee.fr/~polleuxj/Documents/athena_users.pdf Silvaco. (2006, Dec.) ATLAS User’s Manual: Device Simulation Software. Silvaco. Santa Clara, CA. [Online]. Available: http://ridl.cfd.rit.edu/products/manuals/Silvaco/atlas_users.pdf