Quantum computing technologies

The transfer characteristics (source-drain current function of gate source-voltage) were analyzed for qubit SiGe pMOS type transistors, designed by the University of Toronto (UofT) and manufactured in 22 nm technology. The transfer characteristics of the pMOS type transistors have been performed by maintaining the value of the drain voltage at -10 mV and varying the temperature between 50 K and 6 K. The measurements were performed with a cryogenic equipment (able to cool down to 5 K) developed in the frame of the laboratory for microwave (on wafer) measurements up to 67 GHz.

Transfer characteristics of pMOS transistor for (a) different temperature values at a constant drain voltage value and (b) different drain voltage values at a temperature of 1.65 K (cooperation between IMT and University of Toronto)

Measurement set-up  for S paramater up to 140 GHz, in the temperature range of 297K - 6 K.

SEM micrograph of 10 nm wide HSQ lines

Nanolithographic gate lines having  <10 nm resolution

Switches and filters based on vertical carbon nanotubes were designed for applications at frequencies around 60 GHz using both a circuit simulator (NI AWR Design Environment) and a 3D electromagnetic simulator (CST Microwave Studio). The following parameters were used to design the devices: length L= 4.9 mm on the x coordinate and width W = 2.5 mm on the y coordinate. The thickness of the high resistivity silicon (HRSi) substrate is 300 μm, and of the thin silicon oxide (SiO2) layer is 1 μm. The thickness of the gold layer is 500 nm. The parameters S (reflection and transmission coefficient) were obtained as a result of the electromagnetic simulation of the device and the optimal operation of the filters around the frequency of 60 GHz was demonstrated. After the optimization of all the geometric parameters, the GDS files were obtained for the masks necessary for the manufacture of the devices.

a) The three-dimensional structure for filters based on carbon nanotubes obtained with the help of the electromagnetic simulator.	b) Detail from the central area of ​​the device.
a)	b)
c)	d)
S parameters: (a) reflection coefficient at port 1; (b) reflection coefficient at port 2; (c) transmission from port 2 to port 1; (d) transmission from port 1 to port 2 for carbon nanotube filters.

Bow-tie type antennas with an operating frequency of 24 GHz were made on a silicon substrate. This component will be used to harvest RF energy at the operating frequency of 24 GHz using self-switching diodes (SSD) based on molybdenum disulfide (MoS2). The 24 GHz bow-tie antennas with/without SSDs were fabricated using a monolayer of MoS2 deposited on a sapphire and silicon substrate.

Optical pictures for the fabricated devices: (a) 24GHz bow-tie antennas; (b) detail with the gap between the two sides of the antennas; (c) self-switching diodes fabricated using MoS2 by CPW technology; (d) detail with the diode surface on the coplanar line.

1. Antennas and antenna arrays were simulated based on NCG, at 10 and 24 GHz. An array of 2 antennas based on NCG at 10 GHz was simulated, manufactured and characterized, which was characterized in direct current (cc) and in microwaves, both in the near field and in the far field. It was demonstrated the reconfiguration of the array gain depending on the DC voltage applied to the NCG layer.

Reflection coefficient (left) and received power (right) for the antenna array based on NCG at 10 GHz.

2. Types of memtransistors were designed: one of planar FET type with one channel based on NCG deposited on HfZrO and one of interdigitated capacitor (IDC) type on low resistivity silicon, with area-selective wet etched HfZrO between the capacitor digits.

Fabricated IDC (left) and drain current-drain voltage curves with open gate (right)

Design and manufacturing of micromachined, passive circuits elements, monolithically and hybrid integrated receiver front-ends based on silicon and GaAs micromachining

- GaAs membrane supported millimeter wave receiver operating in the 60 GHz frequency range based on the monolithic integration of a Yagi-Uda antenna with a Schottky diode, both having as support the same 2.2 µm thin semi-insulating GaAs membrane
- Novel micromachined lumped bandpass filter for 5.2GHz WLAN applications
- Millimeter wave identification system at 60 GHz
- 77 GHz receiver in LTCC technology

77 GHz receiver designed by IMT Bucharest and processed at VTT Finland

D. Neculoiu, M. Lahti, A. C. Bunea, A. Stefanescu, T. Vaha – Heikkila, Design and Experiments of a 77 GHz Receiver in LTCC Technology, Proceedings of Asia – Pacific Microwave Conference, Melbourne December 2011

Structure of a CRLH CPW directional coupler

G. Sajin, A. C. Bunea, Fl. Craciunoiu, A. Dinescu, M. Zamfirescu, R. Dabu (2011): CRLH mm-Wave Directional Coupler on Silicon Substrate Microprocessed by Laser Ablation. Proceedings of the International IEEE Conference on Microwaves, Communications, Antennas and Electronic Systems, IEEE COMCAS 2011, 07 – 09 Nov. 2011, Tel Aviv, Israel, Paper ID 2A1-1.