Publications de Christian Enz | EPFL Graph Search

Self-heating Effects in RF Region of FDSOI MOSFETs at Cryogenic Temperatures

Christian Enz, Edoardo Charbon, Hung-Chi Han

Radio-frequency (RF) circuits are crucial to qubit manipulation, for which transistor self-heating effects may influence performance and possibly change the quantum state. This paper presents an analytical RF model of FDSOI MOSFETs considering dynamic self ...

Institute of Electrical and Electronics Engineers (IEEE)2025

Cryogenic sEKV Compact Model Applied to 22 NM FDSOI Enabling Low-Temperature Circuit Simulation

Christian Enz, Edoardo Charbon, Hung-Chi Han

IEEE2025

Cryogenic Circuit Performance Prediction Using Design-Oriented Model (SEKV) On 22nm FDSOI

Christian Enz, Edoardo Charbon, Hung-Chi Han

IEEE2025

Modeling of the MOSFET for the Design of Cryo-CMOS Circuits

Christian Enz, Edoardo Charbon, Hung-Chi Han

This paper highlights some of the challenges faced in the modeling of MOSFET devices operating at cryogenic temperature (CT). It will review the most important phenomena, including the saturation of the subthreshold swing (S S) below a critical temperature ...

IEEE Computer Society2024

Analytical Modeling of Short-Channel MOSFET Differential Pair Non-Linearity

Christian Enz, Catherine Dehollain, Andreas Peter Burg, Hung-Chi Han

Energy efficiency is of utmost importance in modern applications. Power consumption optimisation could be improved by a comprehensive analytical modeling of the characteristics of critical blocks in a system. Dynamic range (DR) has a strong effect on the p ...

2024

A Comprehensive Output Conductance Model Valid in All Regions of Inversion

Christian Enz, Hung-Chi Han

The output conductance and transconductance are key small-signal parameters that typically set the dc gain of amplifiers. Although the transconductance can be modelled simply and accurately, modeling the output conductance over a large range of bias and ge ...

IEEE2024

Analytical Modeling of Cryogenic Subthreshold Currents in 22-nm FDSOI Technology

Christian Enz, Edoardo Charbon, Hung-Chi Han

The transistor compact model is crucial but has yet to mature for cryogenic electronics. This paper presents a sophisticated analytical model of the MOSFET subthreshold current at cryogenic temperatures, accounting for the thermionic, hopping, source-to-dr ...

Institute of Electrical and Electronics Engineers2024

An Ultralow Power Short-Range 60-GHz FMCW Radar in 22-nm FDSOI CMOS

Christian Enz, Francesco Chicco

This article presents the design of an ultralow power short-range 57-66 GHz frequency-modulated continuous-wave (FMCW) radar. The transmitter (TX) path includes a BPSK modulator in order to implement a low-IF architecture and it is optimized for short-rang ...

Institute of Electrical and Electronics Engineers2024

Optical Urea Sensing in Sweat for Kidney Healthcare by Sensitive and Selective Non-enhanced Raman Spectroscopy

Christian Enz, Sandro Carrara, Assim Boukhayma, Ata Jedari Golparvar, Mattia Petrelli

Sweat biomarker analysis has attracted much interest in applications ranging from sports to wearable healthcare. Among all the sweat biomolecules, abnormal urea levels have been linked to several complications, particularly renal dysfunction. Here, we repo ...

SPIE-INT SOC OPTICAL ENGINEERING2023

Design of Low-power Analog Circuits in Advanced Technology Nodes using the Gm/ID Approach

Christian Enz, Hung-Chi Han

The Gm/ID approach has proven to be an efficient technique for the design of low-power analog circuits. Until now it was mostly demonstrated on older CMOS technology nodes. In this paper we will show that the Gm/ID methodology still holds for advanced tech ...

IEEE2023

Third-harmonic generation monitoring of femtosecond-laser-induced in-volume functional modifications

Christian Enz, Yves Bellouard, Olivier Bernard, Assim Boukhayma, Andrea Kraxner

During the last two decades, ultrafast in-volume laser-based processing of transparent materials has emerged as a key 3D-printing method for manufacturing a variety of complex integrated photonic devices and micro-parts. Yet, identifying suitable laser pro ...

2023

Design of Cryo-CMOS Analog Circuits using the Gm/ID Approach

Christian Enz, Hung-Chi Han

The Gm/ID approach has proven to be an efficient technique for the design of low-power analog circuits even in advanced technology nodes. It has already been shown that the normalized Gm/ID is actually a universal figure-of-merit (FoM) that is independent ...

IEEE2023

The Fano Noise Suppression Factor and the Gm/ID FoM

Christian Enz, Hung-Chi Han

This paper establishes the close relation that exists between the Fano noise suppression factor F and the Gm/ID FoM showing that F is proportional to the product of the thermal noise excess factor γn and the normalized Gm/ID function. Taking advantage of t ...

IEEE2023

Cryogenic InGaAs HEMTs with Reduced On-Resistance using Strained Ohmic Contacts

Christian Enz, Hung-Chi Han

We present InGaAs HEMTs with optimized cryogenic Ohmic contacts, for low-power qubit readout. We utilize tensile strained contact metals to reduce the barrier resistance, which is a major fraction of RSD, leading to ~50% reduction of RSD at low temperature ...

Institute of Electrical and Electronics Engineers Inc.2023

Analytical Modeling of Source-to-Drain Tunneling Current Down to Cryogenic Temperatures

Christian Enz, Hung-Chi Han

The subthreshold swing (SS) of MOSFETs decreases with temperature and then saturates below a critical temperature. Hopping conduction via the band tail has been proposed as the possible cause for the SS saturation. On the other hand, numerical simulations ...

Institute of Electrical and Electronics Engineers2023

An improved subthreshold swing expression accounting for back-gate bias in FDSOI FETs

Christian Enz, Farzan Jazaeri, Hung-Chi Han

In a MOSFET transistor, the subthreshold swing defines the switching efficiency, and the associated slope factor, or so-called body factor, is a critical parameter in charge-based models. However, in an advanced Fully -Depleted Silicon-On-Insulator (FDSOI) ...

PERGAMON-ELSEVIER SCIENCE LTD2023

Rapid, Sensitive and Selective Optical Glucose Sensing with Stimulated Raman Scattering (SRS)

Christian Enz, Sandro Carrara, Assim Boukhayma, Ata Jedari Golparvar

Optical blood glucose sensing offers pain-free, non-invasive, continuous monitoring with minimum risk of infection since it does not require breaking the skin barrier. Among various optical detection and spectroscopic techniques, only Raman scattering offe ...

IEEE2022

SEKV-E: Parameter Extractor of Simplified EKV I-V Model for Low-Power Analog Circuits

Christian Enz, Hung-Chi Han, Antonio D'Amico

This paper presents the open-source Python-based parameter extractor (SEKV-E) for the simplified EKV (sEKV) model, which enables the modern low-power circuit designs with the inversion coefficient design methodology. The tool extracts the essential sEKV pa ...

IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC2022

Simple Expression of the Thermal Noise Excess Factor for LNA Design

Christian Enz

This paper proposes a simple model of the thermal noise excess factor in saturation gamma(nsat) for short-channel transistors affected by velocity saturation. It is shown that gamma(nsat) in strong inversion and saturation under velocity saturation increas ...

IEEE2022

Cryogenic InGaAs HEMT-Based Switches For Quantum Signal Routing

Christian Enz, Hung-Chi Han

We demonstrate cryogenic switching devices based on HEMT technology for scalable quantum computer (QC) control and readout signal routing. The switches are implemented in a quantum well network design without metal contacts between gates, and exhibit extre ...

IEEE2022