A test pattern to investigate the effect of capping layers on the hot carrier induced photon spectra of MOSFETs

In this paper we report the design and characterization of a simple test pattern suitable to investigate the main effects that the polysilicon gate and the passivation layers induce on the photon spectra emitted by silicon MOSFETs biased in the hot-carrier regime. By comparing of the measured data with numerical calculations of the optical transmittance of the layers covering the emission area we extracted the absorption coefficient of the gate polysilicon over a wide range of photon energies. The effect of the capping layers on the polarization of the emitted light is also discussed