Promos Technologies, Inc

Mosel Vitelic Corporation

Promos Technology, Inc.

Chuck Jang

Zhong Dong

Chia-Shun Hsiao

Ching-Hwa Chen

Jin-Ho Kim

Tai-Peng Lee

Vei-Han Chan

Chunchieh Huang

Dong Jun Kim

Hua Ji

Ching-Yueh Hu

Chung Wai Leung

George Kovall

Steven Ming Yang

Conventional fabrication of sidewall oxide around an ONO-type memory cell stack usually produces Bird's Beak because prior to the fabrication, there is an exposed sidewall of the ONO-type memory cell stack that exposes side parts of a plurality of material layers respectively composed of different materials. Certain materials in the stack such as silicon nitrides are more difficult to oxidize than other materials in the stack such polysilicon. As a result oxidation does not proceed uniformly along the multi-layered height of the sidewall. The present disclosure shows how radical-based fabrication of sidewall dielectric can help to reduce the Bird's Beak formation. More specifically, it is indicated that short-lived oxidizing agents (e.g., atomic oxygen) are able to better oxidize difficult to oxidize materials such as silicon nitride and the it is indicated that the short-lived oxidizing agents alternatively or additionally do not diffuse as deeply through already oxidized layers of the sidewall such as silicon oxide layers. As a result, a more uniform sidewall dielectric can be fabricated with more uniform breakdown voltages along it height.

Method of forming ONO-type sidewall with reduced bird's beak

A method and apparatus are disclosed for reducing the concentration of chlorine and/or other bound contaminants within a semiconductor oxide composition that is formed by chemical vapor deposition (CVD) using a semiconductor-element-providing reactant such as dichlorosilane (DCS) and an oxygen-providing reactant such as NO. In one embodiment, a DCS-HTO film is annealed by heating NO gas to a temperature in the range of about 825&#xb0; C. to about 950&#xb0; C. so as to trigger exothermic decomposition of the NO gas and flowing the heated gas across the DCS-HTO film so that disassociated atomic oxygen radicals within the heated NO gas can transfer disassociating energy to chlorine atoms bound within the DCS-HTO film and so that the atomic oxygen radicals can fill oxygen vacancies within the semiconductor-oxide matrix of DCS-HTO film. An improved ONO structure may be formed with the annealed DCS-HTO film for use in floating gate or other memory applications.

Methods for improving quality of high temperature oxide (HTO) formed from halogen-containing precursor and products thereof and apparatus therefor

Conventional fabrication of top oxide in an ONO-type memory cell stack usually produces Bird's Beak. Certain materials in the stack such as silicon nitrides are relatively difficult to oxidize. As a result oxidation does not proceed uniformly along the multi-layered height of the ONO-type stack. The present disclosure shows how radical-based fabrication of top-oxide of an ONO stack (i.e. by ISSG method) can help to reduce formation of Bird's Beak. More specifically, it is indicated that short-lived oxidizing agents (e.g., atomic oxygen) are able to better oxidize difficult to oxidize materials such as silicon nitride and the it is indicated that the short-lived oxidizing agents alternatively or additionally do not diffuse deeply through already oxidized layers of the ONO stack such as the lower silicon oxide layer. As a result, a more uniform top oxide dielectric can be fabricated with more uniform breakdown voltages along its height. Additionally, adjacent low and high voltage transistors may benefit from simultaneous formation of their gate dielectrics with use of the radical-based oxidizing method.

Method for simultaneously fabricating ONO-type memory cell, and gate dielectrics for associated high voltage write transistors and gate dielectrics for low voltage logic transistors by using ISSG

An ONO-type inter-poly insulator is formed by depositing intrinsic silicon on an oxidation stop layer. In one embodiment, the oxidation stop layer is a nitridated top surface of a lower, and conductively-doped, polysilicon layer. In one embodiment, atomic layer deposition (ALD) is used to precisely control the thickness of the deposited, intrinsic silicon. Heat and an oxidizing atmosphere are used to convert the deposited, intrinsic silicon into thermally-grown, silicon dioxide. The oxidation stop layer impedes deeper oxidation. A silicon nitride layer and an additional silicon oxide layer are further deposited to complete the ONO structure before an upper, and conductively-doped, polysilicon layer is formed. In one embodiment, the lower and upper polysilicon layers are patterned to respectively define a floating gate (FG) and a control gate (CG) of an electrically re-programmable memory cell. In an alternative embodiment, after the middle, silicon nitride of the ONO structure is defined, another layer of intrinsic silicon is deposited, by way of for example, ALD. Heat and an oxidizing atmosphere are used to convert the second deposited, intrinsic silicon into thermally-grown, silicon dioxide. An ONO structure with two thermally-grown, and spaced apart, silicon oxide layers is thereby provided.

Precision creation of inter-gates insulator

Aluminum oxide is deposited by atomic layer deposition to form a high-k dielectric for the interpoly dielectric layer of a non-volatile memory device. The increased capacitive coupling can allow a thicker oxide layer to be used between the floating gate and the control gate, resulting in improved reliability and longer lifetime of the memory cells fabricated according to this invention.

Atomic layer deposition of interpoly oxides in a non-volatile memory device

A method for controlling the position of air gaps in intermetal dielectric layers between conductive lines and a structure formed using such a method. A first dielectric layer is deposited over at least two features and a substrate and an air gap is formed between the at least two features and above the feature height. The first dielectric layer is etched between the at least two features to open the air gap. Then a second dielectric layer is deposited over the etched first dielectric layer to form an air gap between the at least two features and completely below the feature height.

Control of air gap position in a dielectric layer

Methods for improving quality of semiconductor oxide composition formed from halogen-containing precursor

A high density plasma chemical vapor deposition (HDP-CVD) process is used to deposit silicon dioxide in trenches of various widths. The thickness of the silicon dioxide filling both narrow and wide trenches is made more uniform by reducing an HDP-CVD etch to deposition ratio. The lowered etch to deposition ratio is achieved by lowering a ratio of oxygen to silane gas, by lowering the power of a high frequency bias signal, and by lowering the total gas flow rate.

Reduced thickness variation in a material layer deposited in narrow and wide integrated circuit trenches

The floating gate, or the oxide between the floating and control gates, or both are nitrided before the control gate layer is deposited.

Floating gate nitridation

A method and structure to form shallow trench isolation regions without trench oxide grooving is provided. In particular, a method includes a two-step oxide process in which an oxide liner lines the inside surface of a trench and the trench is filled with a bulk oxide layer, preferably using a high density plasma chemical vapor deposition (HDP-CVD) process. The oxide liner and the bulk oxide layer are formed to have similar etch rates. Thus, when etching the oxide liner and the bulk oxide layer between stack structures, a common dielectric top surface is formed that is substantially planar and without grooves.

Trench isolation without grooving

A thin buffer layer of SiON is formed on the top surface of the floating gate, in order to protect the polysilicon surface from attack by atomic chlorine produced during the formation of the high temperature oxide of the ONO stack. The buffer layer can also be formed on other dielectric surfaces which are otherwise subject to adverse conditions in subsequent processing, such as the nitride layer in the ONO dielectric stack.

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Fremont, CA, United States of America

Chuck Jang