摘要:
An IGFET with a gate electrode in a transistor trench adjacent to an isolation trench is disclosed. The trenches are formed in a semiconductor substrate. A gate insulator is on a bottom surface of the transistor trench, insulative spacers are adjacent to opposing sidewalls of the transistor trench, and the gate electrode is on the gate insulator and spacers and is electrically isolated from the substrate. Substantially all of the gate electrode is within the transistor trench. A source and drain in the substrate are beneath and adjacent to the bottom surface of the transistor trench. The isolation trench is filled with an insulator and provides device isolation for the IGFET. Advantageously, the trenches are formed simultaneously using a single etch step.
摘要:
An improved series and/or parallel connection of transistors within a logic gate is presented. The improved connection is brought about by a sacrificial structure on which gate conductors are formed adjacent sidewall surfaces of the sacrificial structure. The sacrificial structure thereby provides spacing between the series-connected or parallel-connected transistors. Upon removal of each sacrificial structure, a pair of transistors can be formed by implanting dopant species into the substrate on opposite sides of the spaced conductors. Beneath what was once a sacrificial structure is a shared implant area to which two transistors are coupled either in series or in parallel. By depositing the gate conductor material and then anisotropically removing the material except adjacent the vertical sidewall surfaces, an ultra short gate conductor can be formed concurrent with other gate conductors within a logic gate.
摘要:
An improved series and/or parallel connection of transistors within a logic gate is presented. The improved connection is brought about by a sacrificial structure on which gate conductors are formed adjacent sidewall surfaces of the sacrificial structure. The sacrificial structure thereby provides spacing between the series-connected or parallel-connected transistors. Upon removal of each sacrificial structure, a pair of transistors can be formed by implanting dopant species into the substrate on opposite sides of the spaced conductors. Beneath what was once a sacrificial structure is a shared implant area to which two transistors are coupled either in series or in parallel. By depositing the gate conductor material and then anisotropically removing the material except adjacent the vertical sidewall surfaces, an ultra short gate conductor can be formed concurrent with other gate conductors within a logic gate.
摘要:
Various processes are provided for producing a p-channel and/or n-channel transistor. The present processes are thereby applicable to NMOS, PMOS or CMOS integrated circuits, any of which derive a benefit from having an asymmetrical LDD structure. The asymmetrical structure can be produced on a p-channel or n-channel transistor in various ways. According, the present process employs various techniques to form an asymmetrical transistor. The various techniques employ processing steps which vary depending upon the LDD result desired. First, the LDD implant can be performed only in the drain-side of the channel, or in the drain-side as well as the source-side. Second, the gate conductor sidewall surface adjacent the drain can be made thicker than the sidewall surface adjacent the source. Thickening of the drain-side sidewall spacer can be achieved either by depositing oxide upon a nitride-bearing film, or by growing additional oxide upon an exposed silicon surface having the source-side sidewall protected from growth. Third, the drain-side can be enhanced relative to the source-side by using an LTA implant. There may be numerous other modifications and alternative processing steps, all of which are described herein. Regardless of the sequence chosen, a barrier implant may be employed to prevent deleterious ingress of p-type implant species into the channel region. The present fabrication sequence reduces source-side resistance to enhance drive current--a desirable outcome for high speed circuits.
摘要:
An IGFET with a gate electrode in a transistor trench adjacent to an isolation trench is disclosed. The trenches are formed in a semiconductor substrate. A gate insulator is on a bottom surface of the transistor trench, insulative spacers are adjacent to opposing sidewalls of the transistor trench, and the gate electrode is on the gate insulator and spacers and is electrically isolated from the substrate. Substantially all of the gate electrode is within the transistor trench. A source and drain in the substrate are beneath and adjacent to the bottom surface of the transistor trench. The isolation trench is filled with an insulator and provides device isolation for the IGFET. Advantageously, the trenches are formed simultaneously using a single etch step.
摘要:
An integrated circuit transistor and method of making the same are provided. The transistor includes a substrate, first and second source/drain regions, and a gate electrode stack coupled to the substrate. The gate electrode stack is fabricated by forming a first insulating layer on the substrate, forming a first conductor layer on the first insulating layer, and forming a metal layer on the first conductor layer. A second insulating layer, such as an interlevel dielectric layer, is coupled to the substrate adjacent to the gate electrode stack. Sidewall spacers and LDD processing may be incorporated. The transistor and method integrate metal and polysilicon into a self-aligned gate electrode stack.
摘要:
The present invention advantageously provides a test structure and method for determining how lithographic patterning of transistor gate conductors laterally spaced from conductors affects the operation of transistors which employ the gate conductors. The test structure includes a sequence of gate conductors interposed above and between a respective sequence of source and drain regions. The test structure further includes a sequence of conductors which have been patterned from the same material as the gate conductors. The conductors are spaced an increasing distance from respective gate conductors. The gate conductors extend beyond the respective source and drain regions by varying distances or by the same distance. Lithographic patterning of the gate conductors and the conductors may result in the edges of the gate conductors and the conductors being substantially round and absent of sharp corners. Further, lithographic patterning may lead to a reduction in the lengths of the gate conductors and the conductors. The length of each gate conductor extends along the same axis as the length of the conductor nearest to the gate conductor.
摘要:
A semiconductor process in which a trench transistor is formed between a pair of planar transistors such that the source/drain regions of the trench transistor are shared with the source/drain regions of the planar transistors. A substrate is provided and first and second planar transistors are formed upon the upper surface of the substrate. The gate dielectric of the trench transistor is vertically displaced below the upper surface of the substrate. The trench transistor shares a first shared source/drain structure with the first planar transistor and a second shared source/drain structure with the second planar transistor. The formation of the trench transistor preferably includes the steps of etching a trench into the substrate, thermally oxidizing a floor of the trench to form a trench gate dielectric, and filling the trench with a conductive material to form a trench gate structure. The trench floor is vertically displaced below the upper surface of the substrate by a trench depth. The trench depth is preferably greater than a junction depth of the source/drain structures. In one embodiment, the formation of the trench transistor further includes, prior to the thermal oxidation of the trench floor, forming first and second ldd structures within the first and second trench ldd regions of the substrate. The first and second trench ldd structures provide conductive paths that extend from a trench channel region located beneath the trench floor to the first and the second shared source/drain structures respectively.
摘要:
A method of fabricating an integrated circuit transistor in a substrate is provided. A gate electrode stack is formed on the substrate. The stack has a first insulating layer, a first conductor layer on the first insulating layer, a second insulating layer on the first conductor layer, and a second conductor layer on the second insulating layer. First and second source/drain regions are formed in the substrate in spaced apart relation to define a channel region underlying the first insulating layer. First and second sidewall spacers are formed adjacent to the gate electrode stack. The second conductor layer and the second insulating layer are sacrificed and a silicide layer is formed on the first conductor layer. The void remaining after removal of the second conductor and insulating layers establishes a large separation between the silicide forming titanium layer and the first conductor layer. The result is a gate electrode stack that is resistant to lateral silicide formation due to silicon diffusion.
摘要:
An integrated circuit fabrication process is provided for forming a transistor having an ultra short channel length dictated by the width of a sidewall spacer which either embodies a gate conductor for the transistor or is used to pattern an underlying gate conductor. In one embodiment, the sidewall spacers are formed upon and extending laterally from the opposed sidewall surfaces of a sacrificial material. The sidewall surfaces of the sacrificial material are defined by forming the sacrificial material within an opening interposed laterally between vertically extending sidewalls which bound a gate dielectric. An upper portion of the gate dielectric is removed to partially expose the sidewall surfaces arranged at the periphery of the sacrificial material. Polysilicon spacers are formed exclusively upon the sidewall surfaces of the sacrificial material to define a pair of gate conductors having relatively small lateral widths. Portions of the gate dielectric not arranged exclusively beneath the gate conductors may be selectively removed. In another embodiment, sidewall spacers are used to protect select regions of a polysilicon gate material arranged exclusively underneath the spacers from being etched. The sidewall spacers are formed upon and extending laterally from sidewall surfaces arranged at the periphery of an opening which extends through a masking or sacrificial material to an underlying polysilicon gate material. The sidewall spacers are sacrificial in that they are removed from the semiconductor topography after they have served their purpose of masking the underlying polysilicon gate material.