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发表于 2011-10-31 12:19:04
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Native channel refers to MOSFETs built with intrisic threshold without threshold adjustment step. MOSFET intricsic threshold depends on the the flatband voltage of the MOS capacitor and the difference of the work functions of the gate/substrate material. For example, the intrisic threshold for an poly-gate NMOS could be as low as zero or tens of millivolts. To make a practical MOSFET, additional step (typically done by Ion implantation) is needed to bring this threshold to around, for example, 600mV. Ion implantation is a brutal process which damages the crystal structure of the channel, even after annealing, there would still some crystal structure defects expected, which will distrub an even current flow, increase the noise of the device. |
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