International Business Machines Corporation

Other

Yujun Li

Jochen C Beintner

William R Tonti

Hiroyuki Akatsu

Kenneth T Settlemyer, Jr

Qiuyi Ye

Jack Allan Mandelman

Ramachandra Divakaruni

Geng Wang

Rama Divakaruni

Lawrence Alfred Clevenger

Dureseti Chidambarrao

Xiangdong Chen

Louis Lu-Chen Hsu

Omer H Dokumaci

Gary Bela Bronner

Qiqing Christine Ouyang

Naim Moumen

Rajesh Rengarajan

Suryanarayan G Hegde

Paul Andrew Ronsheim

Porshia Shane Wrschka

Herbert Lei Ho

Mary Elizabeth Weybright

Kevin McStay

Radhika Srinivasan

Giuseppe La Rosa

A method of fabricating a plurality of FinFETs on a semiconductor substrate in which the gate width of each individual FinFET is defined utilizing only a single etching process, instead of two or more, is provided. The inventive method results in improved gate width control and less variation of the gate width of each individual gate across the entire surface of the substrate. The inventive method achieves the above by utilizing a modified sidewall image transfer (SIT) process in which an insulating spacer that is later replaced by a gate conductor is employed and a high-density bottom up oxide fill is used to isolate the gate from the substrate.

Process for fabrication of FINFETs

A method of fabrication and a field effect device structure are presented that reduce source/drain capacitance and allow for device body contact. A Si based material pedestal is produced, the top surface and the sidewalls of which are oriented in a way to be substantially parallel with selected crystallographic planes of the pedestal and of a supporting member. The pedestal is wet etched with an anisotropic solution containing ammonium hydroxide. The sidewalls of the pedestal become faceted forming a segment in the pedestal with a reduced cross section. The dopant concentration in the reduced cross section segment is chosen to be sufficiently high for it to provide for electrical continuity through the pedestal.

Device fabrication by anisotropic wet etch

A method is presented for fabricating a non-planar field effect device. The method includes the production of a Si based material Fin structure that has a top surface substantially in parallel with a {111} crystallographic plane of the Si Fin structure, and the etching of the Si Fin structure with a solution which contains ammonium hydroxide (NHOH). In this manner, due to differing etch rates in ammonium hydroxide of various Si based material crystallographic planes, the corners on the Fin structure become clipped, and angles between the horizontal and vertical planes of the Fin structure increase. A FinFET device with clipped, or rounded, corners is then fabricated to completion. In a typical embodiment the FinFET device is selected to be a silicon-on-insulator (SOI) device.

Corner clipping for field effect devices

Process for fabrication of FinFETs

A vertical pass transistor used in a DRAM cell for maintaining a low total leakage current and providing adequate drive current is described together with a method of fabricating such a device. The transistor gate is engineered in lieu of the channel. The vertical pass transistor for the DRAM cell incorporates two gate materials having different work functions. The gate material near the storage node is n-type doped polysilicon. The gate material near the bit line diffusion is made of silicide or metal having a higher work function than the n-polysilicon. The novel device structure shows several advantages: the channel doping is reduced while maintaining a high Vt and a low sub-threshold leakage current; the carrier mobility improves with the reduced channel doping; the body effect of the device is reduced which improves the write back current; and the sub-threshold swing is reduced because of the low channel doping.

Method of forming a MOSFET with dual work function materials

Vertical MOSFET with dual work function materials

The structure and method of forming a notched gate MOSFET disclosed herein addresses such problems as device reliability. A gate dielectric (e.g. gate oxide) is formed on the surface of an active area on the semiconductor substrate, preferably defined by an isolation trench region. A layer of polysilicon is then deposited on the gate dielectric. This step is followed by depositing a layer of silicon germanium) (SiGe). The sidewalls of the polysilicon layer are then laterally etched, selective to the SiGe layer to create a notched gate conductor structure, with the SiGe layer being broader than the underlying polysilicon layer. Sidewall spacers are preferably formed on sidewalls of the SiGe layer and the polysilicon layer. A silicide layer is preferably formed as a self-aligned silicide from a polysilicon layer deposited over the SiGe layer, to reduce resistance of the gate conductor. One or more other processing steps (e.g. source and drain implants, extension implants, and pocket lightly doped drain (LDD) implants), gate conductor stack doping, and silicidation are preferably performed in completing the transistor.

Structure and method of forming a notched gate field effect transistor

A method of forming integrated circuits having FinFET transistors includes a method of forming sub-lithographic fins, in which a mask defining a block of silicon including a pair of fins in reduced in width or pulled back by the thickness of one fin on each side, after which a second mask is formed around the first mask, so that after the first mask is removed, an aperture remains in the second mask having the width of the separation distance between the pair of fins. When the silicon is etched through the aperture, the fins are protected by the second mask, thereby defining fin thickness by the pullback step. An alternative method uses lithography of opposite polarity, first defining the central etch aperture between the two fins lithographically, then expanding the width of the aperture by a pullback step, so that filling the widened aperture with an etch-resistant plug defines the outer edges of the pair of fins, thereby setting the fin width without an alignment kstep.

Pull-back method of forming fins in FinFets

A dual work function semiconductor structure with borderless contact and method of fabricating the same are presented. The structure may include a field effect transistor (FET) having a substantially cap-free gate and a conductive contact to a diffusion adjacent to the cap-free gate, wherein the conductive contact is borderless to the gate. Because the structure is a dual work function structure, the conductive contact is allowed to extend over the cap-free gate without being electrically connected thereto.

Dual work function semiconductor structure with borderless contact and method of fabricating the same

An N-channel metal oxide semiconductor (NMOS) driver circuit (and method for making the same), includes a boost gate stack formed on a substrate and having a source and drain formed by a low concentration implantation, and an N-driver coupled to the boost gate stack.

N-channel metal oxide semiconductor (NMOS) driver circuit and method of making same

A method of formation of a deep trench vertical transistor is provided. A deep trench with a sidewall in a doped semiconductor substrate is formed. The semiconductor substrate includes a counterdoped drain region in the surface thereof and a channel alongside the sidewall. The drain region has a top level and a bottom level. A counterdoped source region is formed in the substrate juxtaposed with the sidewall below the channel. A gate oxide layer is formed on the sidewalls of the trench juxtaposed with a gate conductor. Perform the step of recessing the gate conductor below the bottom level of the drain region followed by performing angled ion implantation at an angle &#x3b8;+&#x3b4; with respect to vertical of a counterdopant into the channel below the source region and performing angled ion implantation at an angle &#x3b8; with respect to vertical of a dopant into the channel below the source.

Self-aligned drain/channel junction in vertical pass transistor DRAM cell design for device scaling

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Poughkeepsie, NY, United States of America

Yujun Li