Work

Horizontal Current Bipolar Transistor f T and f max Recovery at Cryogenic Temperatures

Year: 2025

Type: article

Abstract: RF characterization of the Horizontal Current Bipolar Transistor (HCBT) is performed in a cryostat over the temperature range from 300 K down to 20 K. Following the expected decrease of small-signal current gain (h21), cut-off frequency (fT) and maximum frequency of oscillations (fmax) from 300 K to 80 K, a recovery of all parameters is observed below 80 K, in contrast to any other published Si BJT technology. Compared with a commercial bipolar junction transistor (BJT) having a similarfTandfmaxat 300 K, the HCBT demonstrates a 3.2 times higherfTand 2.5 times higherfmaxat 20 K. ThefTrecovery is attributed to the mobility improvement in the freeze-out regime, whereasfmaxincreases even more due to the reduction of the effective collector-base capacitance (CBC) below 80 K. These characteristics could facilitate the use of Si BJTs in cryogenic applications such as quantum computing.

Source: IEEE Electron Device Letters

DOI: 10.1109/led.2025.3617216

Authors: Filip Bogdanović, Lovro Marković, Azra Tabaković, Marko Koričić, Tomislav Suligoj

Institutions: University of Zagreb, Faculty of Electrical Engineering and Computing in Zagreb

Language: English

Topic: Advancements in Semiconductor Devices and Circuit Design

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $2,645

Funder: Hrvatska Zaklada za Znanost