Transistor with asymmetric source/drain overlap

a technology of source/drain overlap and transistor, applied in the field of field-effect transistor, can solve the problems of increasing circuit delay, gate to drain capacitance affecting circuit delay significantly more, and circuit delay being more sensitiv

Inactive Publication Date: 2019-12-26
ELPIS TECH INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This approach allows for improved drive current and reduced circuit delay without the need for precise overlay of source / drain patterning masks, enabling lower resistance on the source side and lower parasitic capacitance on the drain side, thus optimizing transistor performance.

Problems solved by technology

Additionally, circuit delay is more sensitive to gate to drain capacitance than gate to source capacitance.
That is, due to the Miller effect, the gate to drain capacitance can impact circuit delay significantly more than gate to source capacitance.
However, some techniques associated with reducing source / drain resistance to improve drive current often simultaneously increase the gate to drain capacitance, thereby increasing circuit delay.
Similarly, some techniques associated with reducing gate to source / drain capacitance often simultaneously increase source resistance, thereby degrading drive current.

Method used

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  • Transistor with asymmetric source/drain overlap
  • Transistor with asymmetric source/drain overlap
  • Transistor with asymmetric source/drain overlap

Examples

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Embodiment Construction

[0033]Principles of the present invention will be described herein in the context of an illustrative asymmetric field-effect transistor fabricated on a silicon substrate. It is to be appreciated, however, that the specific embodiments and / or methods illustratively shown and described herein are to be considered exemplary as opposed to limiting. Moreover, it will become apparent to those skilled in the art given the teachings herein that numerous modifications can be made to the embodiments shown that are within the scope of the claims. That is, no limitations with respect to the embodiments shown and described herein are intended or should be inferred.

[0034]The figures schematically illustrate an exemplary sequence of fabrication steps that may be employed in obtaining an asymmetric field-effect transistor. Although the overall fabrication method and the structures formed thereby are novel, certain individual processing steps required to implement the method may utilize conventional...

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Abstract

An asymmetric field-effect transistor having different gate-to-source and gate-to-drain overlaps allows lower parasitic capacitance on the drain side of the device and lower resistance on the source side. Source and drain regions having different configurations can be formed simultaneously using the same precursor materials.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is a division of U.S. patent application Ser. No. 16 / 016,454 filed Jun. 22, 2018, the complete disclosure of which is expressly incorporated herein by reference in its entirety for all purposes.BACKGROUND[0002]The present invention relates generally to the electronic arts and, more particularly, to field-effect transistors and their fabrication.[0003]There is a trade-off between source / drain series resistance and gate to source / drain capacitance in the design of metal oxide semiconductor field-effect transistors (MOSFETs). Specifically, FET saturated currents are more sensitive to source resistance and less sensitive to drain resistance. FET drive current improves more with reduced source resistance than with reduced drain resistance. Additionally, circuit delay is more sensitive to gate to drain capacitance than gate to source capacitance. That is, due to the Miller effect, the gate to drain capacitance can impact circuit...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): H01L29/78H01L29/66H01L29/08H01L29/10H01L29/417
CPCH01L29/7851H01L29/66636H01L29/66545H01L21/0217H01L29/66795H01L29/66659H01L29/41791H01L21/31116H01L21/31053H01L29/6656H01L29/0847H01L29/1037H01L21/31111H01L29/7835H01L21/30604H01L21/3086H01L29/785
InventorCHENG, KANGGUOXU, PENGWU, HENGBI, ZHENXING
OwnerELPIS TECH INC