Impact of interface states on MOS transistor mismatch

Mismatch sources in LDMOS devices

“…This signature consists of the mismatch fluc- [4]), and a well-chosen autocorrelation coefficient curve (correlation between [5]. Furthermore, the threshold voltage, V T , and the current factor, β, are extracted (from measurements with V ds = 50 mV) employing three-point extraction with fixed gate overdrive, as for instance described in [6].…”

“…As explained in [5], interface states with random energy, concentration and position are assigned to the interface between the gate oxide and the silicon. The energy is randomly selected in the bandgap of the silicon and the nominal concentration follows a parabolic shape that ranges from 1×10 cm −2 at midgap to 5×10 cm −2 at the extremes.…”

“…Three different mismatch contributors are applied to a tuned device through our doping and interface states randomizer [5] and then simulated using Sentaurus Device. The area, over which the doping and the interface states randomizations are applied, covers the channel as well as the drift region.…”

Interpretation of MOS transistor mismatch signature through statistical device simulations

“…As mentioned in chapter 1, LER and PGB are those that attracted the most attention [14,15,42]. For their importance in the weak inversion operation region of the device, Random Interface state Fluctuations (RIF) are proposed here in this thesis as one of the most important source of variability in MOSFET mismatch after RDF [43]. Furthermore, a third source, especially important when the device operates with elevated currents is discussed in this thesis: the Random Series Resistance fluctuations (RSR).…”

“…Also, when the traps added to the device in the simulator are all with the same energy they will be filled (or emptied) all at the same gate bias, dramatically reducing their impact on the variability. For a correct representation of this physical phenomenon, traps must be randomized in terms of concentration, energy and position along the interface [43]. The results of the investigation of the impact of interface state fluctuations will be discussed in depth in chapter 3.…”