Qualitative analysis method of LDD structure of MOSFET device

Abstract

The invention provides a qualitative analysis method of an LDD structure of an MOSFET (Metal-Oxide-Semiconductor Field-Effect transistor) device. The method comprises the following steps of: A. preparing a dyeing liquor of a source electrode, a drain electrode and an LDD structure according to a volume ratio of HF to HNO3 to acetate acid gracial equal to 1:2:10; B. immersing an MOSFET device to be measured into the dyeing liquor for 5 sec; C. carrying out cross section observation by a field emission scan electron microscope on doped structure zones of the source electrode, the drain electrode and the LDD structure of the MOSFET device, taking photographs of the scanning by the scan electron microscope and measuring junction depths of correlative doped structures; D. carrying out a qualitative determination on whether the LDD structure is employed. Usage of the dyeing liquor formula in the invention enables simple, rapid and economic junction depth confirmation of doped structures of the source electrode, the drain electrode and the LDD structure of a same kind of MOSFET device and rapid qualitative determination on whether the LDD structure is employed in the MOSFET device.

Description

technical field [0001] The invention relates to a qualitative analysis method for the LDD structure of a MOSFET device. Background technique [0002] Metal-Oxide-Semiconductor Field-Effect transistor, (Metal-Oxide-Semiconductor Field-Effect transistor, MOSFET) is a field-effect transistor (field-effect transistor) that can be widely used in analog circuits and digital circuits. MOSFETs can be divided into N-type and P-type MOSFETs according to the polarity of their "channels". They are usually called NMOSFET and PMOSFET. Other abbreviations include NMOS FET, PMOS FET, nMOSFET, pMOSFET, etc. [0003] MOSFETs have continued to shrink in size over the past few decades. In the early integrated circuit MOSFET process, the channel length was on the order of a few microns, but in today’s integrated circuit process, this parameter has been reduced by dozens of times or even more than one hundred times. The mass production of 90nm products, 65nm products, and 45nm products fully il...

AI Technical Summary

Problems solved by technology

The shrinking of the device size certainly increases the integration level and reduces the cost, but on the other hand, it also brings negative effects-short-channel effects: that is, after the channel length is reduced to a certain extent, the source, The proportion of the depletion region of the drain in the entire channel increases, and the amount of charge required to form an inversion layer on the silicon surface under the gate decreases, so the threshold voltage decreases

At the same time, the charge in the depletion region in the substrate along the lateral widening of the channel width increases the threshold voltage

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