Mitigation of Single-Event Effects in SiGe-HBT Current-Mode Logic Circuits

Area of Science:

• Semiconductor device physics
• Radiation effects in electronics
• Integrated circuit design

Background:

• Negative feedback loops in SiGe HBT DC current mirrors are known to improve single-event transient (SET) response.
• Radiation hardening by design (RHBD) is crucial for enhancing the reliability of electronic components in harsh environments.

Purpose of the Study:

• To demonstrate the effectiveness of RHBD techniques applied solely to DC current mirrors in improving SET response within AC signal paths of switching circuits.
• To evaluate the impact of RHBD on current-mode logic (CML) circuits fabricated in SiGe HBT technology.

Main Methods:

• Fabrication of four CML circuits in 130 nm SiGe HBT technology, with and without RHBD current mirrors.
• Implementation of two RHBD techniques in DC current mirrors: internal negative feedback and addition of a large capacitor.
• Analysis of combined RHBD techniques for overall SET performance.
• Characterization of SET response using a two-photon-absorption laser-induced single-event environment.

Main Results:

• Significant improvements in SET response were observed in the AC signal paths of CML circuits utilizing RHBD current mirrors.
• The peak output transient current was notably reduced.
• The settling time following a laser-induced event was significantly shortened.

Conclusions:

• RHBD techniques applied exclusively to DC current mirrors effectively enhance SET immunity in the AC signal paths of CML circuits.
• These findings offer a method for improving the radiation tolerance of switching circuits without hardening the entire circuit.
• The study validates the efficacy of negative feedback and capacitive hardening in current mirrors for SET mitigation.