Compact modeling and electrical characterization of electron devices

Presentation of the nanoelectronics research activities of the Model team

The motivation for the activities carried out within the Electronic-THz team lies in Europe’s societal challenges such as Smart cities, sustainable health and social care, security and environment. We expect that our research will open the route to novel applications in communication, security, health, life science and environmental monitoring. For example, THz active electronic devices could enable products such as wireless communication links with transmission rates well above 1.5Tbit/s for the beyond 5G/6G era. The COVID-19 crises learnt us that performant communication systems for widespread use of home office, video conferences, etc. are of utmost importance for keeping economy alive, even under shutdown conditions. The notion of resilience is thus gaining importance in the political sphere and is currently resonating with the general public. Mastering the value chain of the territory’s strategic sectors such as the communication system is an important issue, at least at the European level. THz based electronic systems, however, are not only restricted to communication systems. New applications can be imagined, such as cancer cell identification cameras or handheld portable terahertz sensor systems for remote detection of dangerous agents.

Today, THz radiation is already used in an increasingly wide spectrum of applications like security scanners, THz spectroscopy or inspection of pharmaceuticals or other products that are already packaged. However, the THz systems for these applications are expensive, require large footprints and are hence limited in their applicability. The availability of a THz technology suitable for system-on-chip or system-on-package integration as investigated in our team would rapidly change the situation, as it would enable inexpensive, lightweight and mobile THz devices and systems. The design and implementation of high-speed circuits require individual transistors to be able to operate in the THz range. The characteristics of SiGe HBTs from BiCMOS technologies are therefore well within the THz range thanks to maximum oscillation frequency ranging from 400 to 700 GHz. This technology offers a good trade-off in terms of efficiency, cost and functionality thanks to presence of MOSFET devices for digital data processing.

Thus, the contribution of our team to reach the objectives of THz silicon circuit concern:

Measurement and modelling up to 500 GHz of a SiGe HBT transistor Phase(S)

Peak fT and fMAX values of high-speed SiGe HBT technologies

THz VNA and associated probe station (up to 750 GHz)

EM model of 220-325 GHz probe built using a tomographic image

EM simulation at 220 GHz with probe a) 140-220 GHz, and probe b) 220-325 GHz showing the difference in EM field confinement at the output of the two probes

Measurement and modelling up to 500 GHz of a SiGe HBT transistor Mag(S)

Here are some highlights of the work carried out by our group in recent years as part of projects, PhDs or postdocs :

S-parameter characterization in the mmW and THz range:

We have made the first measurements of an HBT on a silicon substrate up to 500 GHz
A new simulation methodology has been proposed for the 500 GHz S-parameter measurement bench using electromagnetic and SPICE simulation
Accurate EM models have been developed of GGB Picoprobe and Formfactor probes up to 500GHz
Improvement of the layout of test structures for HF measurement
TCAD support used as an arbiter to validate or invalidate our transistor measurement results

Electrothermal modelling of SiGe HBTs:

Transistor architecture:

Model teams skills

Physics of SiGe HBT

Electro-thermal characterization and modelling

Pulsed IV and RF characterization

Electromagnetic simulation with HFSS (probe modelling on test structure, calibration methodology emulation)

Compact modeling of transistors using Verilog A code

On wafer DC and S parameters characterization up to 750 GHz

Advanced calibration (on wafer TRL, 16 terms, SOLT) and de-embedding methodology for S parameter measurements

TCAD simulation (semiconductor device) with SDevice

Partners

Collaborations and partners

For the various research projects underway, the IMS Bordeaux laboratory and its teams rely on strong partnerships and collaborations, which allow for the creation of a synergy of strengths and a sharing of technical and human resources