Improved designs of Si-based quantum wells and Schottky diodes for IR detection

• SiGe (C)/Si(C) multi quantum wells (MQWs) are evaluated to detect IR radiation.
• Schottky diodes (SDs), individually or in series with MQWs are also fabricated.
• Detectors consisted of MQWs in series with SD show excellent thermal sensing.
• The noise values are also extremely low for MQWs in series with SD.

Novel structures of intrinsic or carbon-doped multi quantum wells (MQWs) and intrinsic or carbon-doped Si Schottky diodes (SD), individually or in combination, have been manufactured to detect the infrared (IR) radiation. The carbon concentration in the structures was 5 × 1020 cm− 3 and the MQWs are located in the active part of the IR detector. A Schottky diode was designed and formed as one of the contacts (based on NiSi(C)/TiW) to MQWs where on the other side the structure had an Ohmic contact. The thermal response of the detectors is expressed in terms of temperature coefficient of resistance (TCR) and the quality of the electrical signal is quantified by the signal-to-noise ratio. The noise measurements provide the K1/f parameter which is obtained from the power spectrum density. An excellent value of TCR = − 6%/K and K1/f = 4.7 × 10− 14 was measured for the detectors which consist of the MQWs in series with the SD. These outstanding electrical results indicate a good opportunity to manufacture low cost Si-based IR detectors in the near future.