Method for extracting flat-band voltage and threshold voltage of MOSFET (metal-oxide-semiconductor field effect transistor) based on current generation of grid-control drain electrode

Abstract

A method for extracting flat-band voltage and threshold voltage of an MOSFET (metal-oxide-semiconductor field effect transistor) based on current generation of a grid-control drain electrode belongs to the filed of micro electronic technique, is used for extracting VFB and VTH through the variation of grid-control generated current caused by the fact that a channel of the MOSFET changes from an accumulation region, an exhaustion region to a transoid region, and includes the following steps: an electrode at the source end of the MOSFET is hung in the air, a small drain voltage VD is exerted on the drain electrode, and the absolute valve of the VD is smaller than or equals to 0.2 V; the gate voltage VG is scanned, the channel changes from the accumulation region to the transoid region, and the grid-control generated current is measured under the drain bias VD; secondary partial differentiation operation for the obtained grid-control generated current curve IGD is performed to obtain the relation curve of the secondary derivative and the VG; the curve forms three peak value points, so as to obtain the peak value point corresponding to the rise edge and the peak value corresponding to the decline edge; the flat-band voltage VFB can be obtained through forming a vertical at the peak value point corresponding to the rise edge and enabling the vertical to be intersected with a grid voltage shaft; and the threshold voltage VTH can be obtained through forming a vertical at the peak value point corresponding to the decline edge and enabling the vertical to be intersected with the grid voltage shaft.

Description

Technical field: [0001] The invention relates to the technical field of microelectronics, in particular to a method for extracting flat-band voltage and threshold voltage of a device by using gate control to generate current in a MOSFET. Background technique: [0002] The flat band voltage in the MOSFET (V IB ) voltage, threshold voltage (V TH ) are two very important electrical parameters. The flat-band voltage reflects the charge in the gate oxide layer, generally testing V FB It is tested by non-DC methods such as capacitance voltage (CV). The test method is to apply a pulse voltage of a certain frequency on the grid, and then measure the capacitance C between the grid and the substrate. According to the comparison between the actual CV curve and the ideal CV curve, V FB . This method test needs a frequency generator, so the experimental equipment is complicated. Moreover, obtaining an ideal CV curve requires many process parameters, and device users rarely obtain ...

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Problems solved by technology

In summary, direct observation of the current generated by gating to determine V FB and V TH The traditional methods often cannot eliminate the artificial imprecision in the actual test

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