Analysis of near-IR photon emissions from 50-nm n- and p-channel Si MOSFETs

Photon emission from n- and p-channel transistors having 50-nm effective lengths and operating in saturation were obtained by using a photon-emission microscope equipped with an HgCdTe detector. Emission spectra were acquired in the near-IR or low photon energy range (0.85-1.1 eV) and fitted to three models: Brehmsstrahlung, direct hot-hole transitions, and direct hot electron transitions. The results show that emissions in both n-channel and p-channel devices have similar Gaussian profiles, implying that the same emission mechanism is occuring in both devices. Emissions from both devices are largely due to photons generated from direct hot electron transitions within the conduction band. The mechanism is modeled as a Gaussian intensity distribution modulated by Si absorption effects since emissions were acquired through the backside.