Method to tailor location of peak electric field directly underneath an extension spacer for enhanced programmability of a prompt-shift device

Abstract

A prompt-shift device having reduced programming time in the sub-millisecond range is provided. The prompt-shift device includes an altered extension region located within said semiconductor substrate and on at least one side of the patterned gate region, and an altered halo region located within the semiconductor substrate and on at least one side of the patterned gate region. The altered extension region has an extension ion dopant concentration of less than about 1E20 atoms / cm3, and the altered extension region has a halo ion dopant concentration of greater than about 5E18 atoms / cm3. The altered halo region is in direct contact with the altered extension region.

Description

RELATED APPLICATION[0001]This application is a divisional of U.S. Ser. No. 12 / 130,460, filed May 30, 2008, the entire contents of which are incorporated herein by reference.FIELD OF THE INVENTION[0002]The present invention relates to a nonvolatile memory cell. More particularly, the present invention relates to a nonvolatile memory cell including at least one field effect transistor (FET) that has enhanced programmability. The invention also provides a method of fabricating such a nonvolatile memory cell.BACKGROUND OF THE INVENTION[0003]In the semiconductor industry, it is oftentimes desirable to fabricate a very large-scale integrated (VLSI) circuit which includes a one-time programmable (OTP) nonvolatile memory element that can be programmed either during wafer probing or after packaging of the semiconductor die. For example, programming of an OTP nonvolatile memory element is used to provide self-contained identification information about an individual IC die or die revision. OTP...

AI Technical Summary

Benefits of technology

The invention provides a method to enhance the programmability of a prompt-shift device by altering the extension and halo implants, instead of simply omitting them. This method allows for faster programming times and reduces the programming time to sub-millisecond times. The invention uses an altered halo / extension implant to adjust the junction profile and enhance the electric field directly beneath the extension dielectric spacer. The no additional mask embodiment of the invention permits the formation of asymmetric, yet altered halo / extension implant regions. The halo ion implant includes a first ion implant step, followed by a second ion implant step. The invention also includes a method to form a source / drain dielectric spacer onto exposed surfaces of the extension dielectric spacer.

Problems solved by technology

The required programming voltage of prior art fuses and antifuses to implement OTP nonvolatile memory storage is quite high (on the order of 10-12 volts) and oftentimes the high-programming voltages must be routed to other circuits in the IC which are not typically capable of withstanding such high voltages.

In some instances, extra processing steps are needed which increase the overall production cost of the IC die.

In addition to requiring high-programming voltages, prior art fuses and antifuses occupy a large space on the IC die which detracts from the space were other ICs devices can be formed.

Although the prompt-shift device disclosed in the above references provides a means for programming a nonvolatile memory cell, the prior art prompt-shift devices require extremely long (on the order of about 1 to about 5 seconds) programming times.

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