Fast determination of the effective channel length and the gate Oxide thickness in polycrystalline Silicon MOSFET´s

MOSFET´s with variable channel lengths have been fabricated in both mono- and fine-grained polycrystalline silicon. We present a new method based upon a simple CV technique, to measure the effective channel length and gate oxide thickness. The channel-length reduction of the poly-Si MOSFET´s was about 7.8 µm from which an effective lateral diffusion coefficient at 1000°C of phosphorus of 5 × 10^-13cm²/s was calculated. The electron mobility was in the range of 10-20 cm²/V.s and the threshold voltage was about 17 V. The MOSFET´s in mono-Si have been used as a reference. The results of measurements on these devices are in agreement with literature.