[paper] FDSOI Threshold Voltage Model

Hung-Chi Han1, (Student, IEEE), Zhixing Zhao2, Steffen Lehmann2,

Edoardo Charbon1, (Fellow, IEEE), and Christian Enz1 (Life Fellow, IEEE)

Novel Approach to FDSOI Threshold Voltage Model Validated at Cryogenic Temperatures

in IEEE Access, DOI: 10.1109/ACCESS.2023.3283298

1 Ecole Polytechnique Fédérale de Lausanne (EPFL), 2000 Neuchâtel, Switzerland
2 GlobalFoundries, 01109 Dresden, Germany

Abstract: The paper presents a novel approach to to the modeling of the back-gate dependence of the threshold voltage of Fully Depleted Silicon-On-Insulator (FDSOI) MOSFETs down to cryogenic temperatures by using slope factors with a gate coupling effect. The FDSOI technology is well-known for its capability to modulate the threshold voltage efficiently by the back-gate voltage. The proposed model analytically demonstrates the threshold voltage as a function of the back-gate voltage without the pre-defined threshold condition, and it requires only a calibration point, i.e., a threshold voltage with the corresponding back-gate voltage, front- and back-gate slope factors, and work functions of front and back gates. The model has been validated over a wide range of the back-gate voltages at room temperature and down to 3 K. It is suitable for optimizing low-power circuits at cryogenic temperatures for quantum computing applications

FIG: Room temperature back-gate coefficient η versus VT−VB for an n-type conventional well (RVT) FDSOI FET with 1 µm of gate length and width. The θ=0 happens at VT−VB = −0.63V due to −0.63V of the front-back gate work function difference 

Acknowledgment: The authors would like to thank Claudia Kretzschmar from GlobalFoundries Germany and GlobalFoundries University Partnership Program for providing 22 FDX® test structures and support. Hung-Chi Han would like to thank Davide Braga from Fermi National Accelerator Laboratory for his valuable support. This project has received funding from the European Union’s Horizon 2020 Research & Innovation Program under grant agreement No. 871764. SEQUENCE.

[paper] InP HEMTs for future THz applications

J.Ajayan^a, D.Nirmal^b, Ribu Mathew^c, Dheena Kurian^d, P.Mohankumar^e, L.Arivazhagan^b, D.Ajitha^f

A critical review of design and fabrication challenges in InP HEMTs 

for future terahertz frequency applications

Materials Science in Semiconductor Processing

Volume 128, 15 June 2021, 105753

  
a SR University, Warangal, Telangana, India
b Karunya Institute of Technology and Sciences, Coimbatore, Tamilnadu, India
c VIT Bhopal University, Bhopal, Madhya Pradesh, India
d Kerala Technological University, Trivandrum, Kerala, India
e Sona College of Technology, Salem, Tamilnadu, India
f Sreenidhi Institute of Science and Technology, Hyderabad, Telangana, India

Abstract: This article critically reviews the materials, processing and reliability of InP high electron mobility transistors (InP HEMTs) for future terahertz wave applications. The factors such as drain current (ID) over 1200 mA/mm, transconductance (gm) over 3000 mS/mm, cut off frequency (fT) over 700 GHz and maximum oscillation frequency (fmax) over 1300 GHz makes InP HEMTs suitable for Terahertz wave applications. Furthermore, low DC power consumption and outstanding low noise performance makes InP HEMT most appropriate transistor technology for the development of space based receivers. This review article critically assesses the challenges in miniaturization of InP HEMTs, doping strategies in InP HEMTs, buried platinum technology, impact of annealing process and temperature, influence of electron and proton irradiation, thermal and bias stress on the reliability of InP HEMTs, cavity and gating effects and influence of trapping effects. InP HEMTs are very much preferable in applications like radio astronomy, terahertz optical and wireless communication systems, atmospheric imaging and sensing, automotive radar, ground based receivers in deep space networks, terahertz imaging and sensing, biomedical applications, security screening, video conferencing & real time multimedia file transfer, high speed and ultra low power digital integrated circuits.

Fig: 3D representation of InP high electron mobility transistor (InP HEMT)