Shallow defects responsible for GR noise in MOSFETs

The extraction of bulk silicon defect information using MOSFET noise analysis is discussed. The calculation of generation-recombination (GR) trapping parameters, from noise-measurements, including a new approach to estimating defect densities, is outlined. The defect density calculation involves estimating the size of a volume, in the depletion layer of the MOSFET, which is considered to contain all the defects actively contributing to the observed noise. These techniques are then used to extract information from n-channel rapid thermal annealed (RTA) MOSFETs that exhibited pronounced GR noise. Hole traps at energies 0.26 and 0.42 eV above the valence band were found, which compares favorably with previous reports of such defects in RTA diode structures. For high-temperature anneals (>1050°C) in one particular set of samples a trap of energy 0.165 eV was responsible for a rise in the E_N(f) noise of two orders of magnitude. The origins and implications of the observed defects are discussed, and the validity of the data extraction techniques for these samples is reviewed