Hot luminescence from CMOS circuits: A picosecond probe of internal timing

Abstract

Carrier transport in submicron silicon CMOS field effect transistors demonstrates strong hot carrier effects. When a gate of a CMOS circuit changes its logic state, we show that a picosecond pulse of hot luminescence is emitted. The source of these switching-induced emission pulses is discussed. Although the emission is quite weak, it can be simultaneously imaged and time-resolved. An analysis of the emission leads to detailed, quantitative information about the internal operation of the circuit. Examples of such analysis, showing circuit timing, propagation delays, and internal voltage changes, are given. An example of the use of the switching-induced emission in the analysis of static emission measurements is also given.