TWI600122B - Sonos device and method for fabricating the same - Google Patents

Description

矽-oxide-nitride-oxide-germanium element and manufacturing method thereof

The present invention relates to a SONOS element and a method of fabricating the same.

The non-volatile memory device is widely used because it has a characteristic that the stored data is not lost due to power supply interruption. Non-volatile memory devices widely used today include read-only-memory (ROM), programmable-read-only memory (PROM), erasable and programmable Erasable-programmable-read-only memory (EPROM) and electronically erasable-programmable-read-only memory (EEPROM). Among them, electronic erasable programmable read-only memory is different from other non-volatile memory in that they can use electronic to program and erase.

At present, the direction of product development in EEPROM devices is focused on increasing the speed of stylization, reducing the voltage during programming and reading, prolonging the time for data storage, reducing the erasing time of memory cells, and reducing the size of memory components. . In addition, some flash memory arrays today use a dual poly-Si gate formed by a stack of two-layer polysilicon, and in this gate structure, polysilicon is usually oxide- A dielectric material composed of an oxide-nitride-oxide (ONO) is used as a spacer to store electrons from the substrate into the underlying polysilicon to achieve storage. The function of storing data. However, the memory array formed by the double-layer polysilicon gate is more difficult to increase the memory capacity because it can store only a single bit of data. Therefore, another derivative flash memory uses 矽-oxide-nitride-oxide-矽 (SONOS) as a data storage unit, and can be used as a transistor to store two bits at the same time. The function is to reduce the size of the component and increase the capacity of the memory. The operation of the SONOS device is exemplified as follows.

When the SONOS memory is programmed, the charge is transferred from a substrate to the tantalum nitride layer in the ONO structure. For example, the user first applies a voltage to the gate and the drain and establishes a vertical electric field and a lateral electric field, and then increases the speed of the electron along the channel by these electric fields. . As the electron moves along the channel, a portion of the electrons will gain sufficient energy to trap trapped in the tantalum nitride layer of the ONO structure across the potential barrier of the bottom ceria layer. Since the electric field near the bungee zone is the strongest, electrons are usually trapped in areas close to the bungee. Conversely, when the operator reverses the potential applied to the source and drain regions, the electrons travel in the opposite direction along the channel and are implanted into the tantalum nitride layer near the source region. Since a portion of the tantalum nitride layer is not electrically conductive, these charges introduced into the tantalum nitride layer tend to remain localized. Thus, depending on the applied voltage, the charge can be stored in different regions of the single tantalum nitride layer.

However, in today's SONOS memory architecture, the efficiency of trapping charge and retaining charge is still not perfect, including insufficient trapped sites or trapped charges. Easy to lose and other shortcomings. Therefore, how to improve the existing SONOS architecture to improve the overall efficiency and reliability of components is an important issue today.

A preferred embodiment of the invention discloses a germanium-oxide-nitride-oxide-germanium (SONOS) device comprising a substrate; a first oxide layer disposed on the substrate; and a silicon-rich trap layer (silicon- a rich trapping layer) disposed on the first oxide layer; a nitrogen-containing layer disposed on the germanium-rich trap layer; a silicon-rich oxide layer disposed on the nitrogen-containing layer; and a polysilicon layer A layer is disposed on the cerium-rich oxide layer.

In accordance with another embodiment of the present invention, a method of making a bismuth-oxide-nitride-oxide-germanium (SONOS) device is disclosed. A substrate is first provided and then a first oxide layer is formed on the substrate. Forming a tantalum nitride layer on the first oxide layer, performing a first silane soak process, introducing ammonia gas and methane to form a germanium-rich trap layer on the first oxide layer. Forming a nitrogen-containing layer on the germanium-rich layer to form a germanium-rich oxide layer on the nitrogen-containing layer and forming a polysilicon layer on the germanium-rich oxide layer.

12‧‧‧Base

14‧‧‧Oxide layer

16‧‧‧Fulfillment

18‧‧‧矽 nitride layer

20‧‧‧ rich layer

22‧‧‧Nitrogen-containing layer

24‧‧‧rich oxide layer

26‧‧‧Oxide layer

28‧‧‧Polysilicon layer

1 is a schematic diagram of fabricating a SONOS memory in accordance with a preferred embodiment of the present invention.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of fabricating a SONOS memory according to a preferred embodiment of the present invention. As shown in FIG. 1, a substrate 12 is first provided, such as a substrate composed of gallium arsenide, a silicon on insulator (SOI) layer, an epitaxial layer, a germanium layer, or other semiconductor substrate material. Then forming a passivation oxide layer (tunnel Oxide, for example, an oxide layer 14 on the substrate 12, and then a silicon-rich trapping layer 16 is formed over the oxide layer 14.

In accordance with a preferred embodiment of the present invention, the germanium-rich cladding layer 16 can include a tantalum nitride layer 18 and a silicon-rich layer 20, such as a silicon-rich SiN layer. Or a silicon-rich SiON layer. In other words, the rich germanium compensation layer 16 may comprise a composite layer composed of a tantalum nitride layer 18 and a germanium-rich tantalum nitride layer, or a composite of a tantalum nitride layer 18 and a germanium-rich tantalum oxide layer. Floor.

According to a preferred embodiment of the present invention, if a composite layer of a tantalum nitride layer 18 and a germanium-rich tantalum nitride layer is to be formed, an ammonia soak process may be performed on the oxide layer 14, followed by ammonia. Gas and silane are used in conjunction with a microwave plasma assisted chemical vapor deposition (microwave PECVD) process to form a tantalum nitride layer 18 on the oxide layer 12. Then, a silane soak process is performed on the tantalum nitride layer 18 in a plasma off state, and then ammonia gas and helium methane are introduced in a plasma on state to form a The germanium-rich layer 20 composed of the germanium-rich tantalum nitride layer forms a germanium-rich trapped layer 16 composed of a tantalum nitride layer 18 and a germanium-rich tantalum nitride layer on the oxide layer 14.

On the other hand, if a composite layer of the tantalum nitride layer 18 and the yttrium-rich yttria layer is to be formed, an ammonia gas immersion process may be performed on the oxide layer 14 first, followed by ammonia gas and helium methane, and a microwave is used in combination. A plasma assisted chemical vapor deposition process is performed to form a tantalum nitride layer 18 on the oxide layer 14. Subsequently, a tantalum methane immersion process is performed on the tantalum nitride layer 18 in a plasma-closed state, and then ammonia gas, oxygen gas and helium methane are introduced into the plasma-opening state to form a layer of yttrium-rich yttrium oxide. Rich layer 20, so in oxygen On the formation layer 14, a germanium-rich trapping layer 16 composed of a tantalum nitride layer 18 and a germanium-rich oxynitride layer is formed.

According to a preferred embodiment of the present invention, the thickness of the tantalum nitride layer 18 is preferably less than 10 angstroms, and the germanium-rich layer 20, including the germanium-rich tantalum nitride layer or the germanium-rich tantalum nitride layer, has a thickness of less than 15 angstroms, but is not limited. herein.

In addition, according to an embodiment of the present invention, a helium methane immersion process is performed to form a ruthenium-enriched trap layer, and a helium gas can be selectively used for pre-cleaning, and the temperature of the pre-cleaning is preferably controlled higher than Celsius. 300 degrees. Secondly, the methane methane immersion can be carried out in the same chamber tool in an atmospheric or sub-atmospheric environment, which is within the scope of the present invention.

A nitrogen-containing layer 22 is then formed over the germanium-rich fill layer 16, wherein the nitrogen-containing layer 22 can comprise a tantalum nitride layer or a hafnium oxynitride layer. Similar to the manner of forming the germanium-rich trap layer 16, if a tantalum nitride layer is to be formed into a nitrogen-containing layer, ammonia gas and germanium methane may be introduced to form a tantalum nitride layer. If a layer of arsenide is desired to be a nitrogen-containing layer, ammonia, oxygen and helium methane may be directly introduced to form a ruthenium oxynitride layer. In accordance with a preferred embodiment of the present invention, the thickness of the nitrogen-containing layer 22 is preferably between 10 and 30 angstroms, but is not limited thereto.

In addition, the germanium-rich germanium layer 16 of the present invention includes the foregoing tantalum nitride layer and the germanium-rich tantalum nitride layer, and the tantalum nitride layer and the germanium-rich germanium nitride layer, and the like, and the nitrogen-containing layer 22 Two material configurations, such as a tantalum nitride layer and a hafnium oxynitride layer, may also be included. However, in accordance with a preferred embodiment of the present invention, when the germanium-rich germanium layer 16 is composed of a tantalum nitride layer and a germanium-rich tantalum nitride layer, The nitrogen-containing layer 22 is preferably composed of a tantalum nitride layer. And when the rich sag layer 16 When the tantalum nitride layer and the yttrium-rich yttria layer are formed, the nitrogen-containing layer 22 is preferably composed of a ruthenium oxynitride layer. However, it should be noted that the combination of the preferred embodiment is exemplified by the above materials, but the material arrangement of the rich layer 16 and the nitrogen-containing layer 22 can be arbitrarily combined according to the requirements of the product, and is not limited thereto. According to the configuration, the nitrogen-containing layer 22 is subjected to a methane immersion process in the plasma-off state, and then oxygen and helium methane are introduced into the plasma-opening state to form a cerium-rich oxide layer 24 on the nitrogen-containing layer 22.

A further oxide layer 26 can then be selectively formed on the germanium-rich oxide layer 24, followed by a control gate, such as a polysilicon layer 28, on the oxide layer 26, thereby completing a preferred embodiment of the present invention. The production of the main unit in the memory. Then, a spacer (not shown) is formed on the sidewall of the main body unit, and a select gate, a source/drain region, an interlayer dielectric layer, and a self-aligned metal telluride may be formed according to a process or a product requirement. (salicide), contact plug and other components, no additional description here.

It should be noted that the SONOS memory disclosed in the preferred embodiment has a germanium-rich germanium oxide layer 24 and a germanium oxide layer 26 disposed between the nitrogen-containing layer 22 and the polysilicon layer 28, but is not limited to this design. In the present invention, the arrangement of the yttrium oxide layer 26 may be omitted according to the requirements of the product, and only one yttrium-rich yttrium oxide layer 24 is disposed between the nitrogen-containing layer 22 and the polysilicon layer 28, or the yttrium-rich yttrium oxide layer 24 is omitted. Only the original ruthenium oxide layer 26 is disposed between the nitrogen-containing layer 22 and the polysilicon layer 28 to complete the fabrication of another SONOS device.

In addition, according to other embodiments of the present invention, a tantalum nitride layer 18 is formed. The three layers of the nitride-containing material layer, such as the germanium layer 20 and the nitrogen-containing layer 22, are not limited to the above-disclosed methods, and may be selected by ion implantation or microwave plasma-assisted chemical vapor deposition (microwave PECVD). ), pulse laser or high energy radiation.

Next, all of the nitrogen-containing material layers in the above embodiments, such as the germanium-rich trap layer 16 and the nitrogen-containing layer 22, and/or all of the ONO stack structures, including the oxide layer 14, the germanium-rich trap layer 16, and the nitrogen-containing layer 22 The ruthenium-rich oxide layer 24 and the oxide layer 26 are preferably completed in the same reaction chamber, but are not limited thereto.

Next, the present invention may alternatively replace the polysilicon layer 28 with other materials such as metal or composite metal to complete another type of memory device. This embodiment is also within the scope of the present invention.

In addition, according to the above process, the present invention further discloses a SONOS device structure, which mainly comprises a substrate 12, an oxide layer 14 is disposed on the substrate 12, a germanium-rich cladding layer 16 is disposed on the oxide layer 14, and a nitrogen-containing layer 22 is provided. A rich germanium oxide layer 24 is disposed on the nitrogen-rich layer 22, an oxide layer 26 is disposed on the germanium-rich oxide layer 24, and a poly germanium layer 28 is disposed on the oxide layer 26.

In accordance with a preferred embodiment of the present invention, the height of the ONO stack structure in the SONOS device is preferably between 30 and 60 angstroms, and wherein the thickness of the tantalum nitride layer 18 in the germanium-rich trap layer 16 is preferably less than 10 angstroms and is rich. Layer 20 preferably has a thickness of less than 15 angstroms. Next, the thickness of the nitrogen-containing layer 22 is preferably between 10 and 30 angstroms, and the thickness of the yttrium-rich oxide layer 24 is preferably less than 15 angstroms.

According to the foregoing process and structure, the SONOS device of the present invention mainly has the following features and advantages: First, the present invention preferably adds two additional interface layers in the ONO stack structure of the conventional SONOS device, including a rich germanium trapping layer 16 And a ruthenium-rich oxide layer 24. The entangled layer 16 of the present invention, including the tantalum nitride layer and the germanium-rich tantalum nitride layer of the above embodiment, and the tantalum nitride layer and the germanium-rich germanium oxynitride layer are preferably used for upgrading. The ability to trap charge. For example, the first layer of material in the germanium-rich layer 16 , such as a tantalum nitride layer, is preferably used as a barrier to make it easier to be trapped when the charge enters the rich trap layer 16 and At the same time avoid the trapped charge loss. The second layer of material in the rich trapping layer 16, such as the above-described yttrium-rich tantalum nitride layer or the yttrium-rich yttrium oxynitride layer, can provide a larger number of trapping sites and simultaneously The charge material of the host material layer.

Secondly, the germanium-rich oxide layer 24 of the present invention has a larger trapped charge position than the germanium-rich tantalum nitride layer or the germanium-rich tantalum nitride layer in the germanium-rich trap layer 16, so that the charge is not easily trapped. Easy to lose. By virtue of the arrangement of the germanium-rich oxide layer 24, the present invention allows the charge near the top of the nitrogen-containing layer 22 to flow more easily out of the entire element. In summary, according to the above proposed architecture, the present invention can utilize the two layers of the germanium-rich trapping layer and the germanium-rich oxide layer to improve the efficiency of trapping and retaining charges of existing SONOS components. The disadvantages mentioned above, thereby improving the overall performance of the entire memory component.

12‧‧‧Base

14‧‧‧Oxide layer

16‧‧‧Fulfillment

18‧‧‧矽 nitride layer

20‧‧‧ rich layer

22‧‧‧Nitrogen-containing layer

24‧‧‧rich oxide layer

26‧‧‧Oxide layer

28‧‧‧Polysilicon layer

Claims (18)

A germanium-oxide-nitride-oxide-germanium (SONOS) device comprising: a substrate; a first oxide layer disposed on the substrate; a tantalum nitride layer disposed on the first germanium oxide layer; a germanium-rich tantalum layer is disposed on the tantalum nitride layer; a nitrogen-containing layer is disposed on the germanium-rich tantalum nitride layer; a silicon-rich oxide layer is disposed on the nitrogen-containing layer; And a polysilicon layer is disposed on the germanium-rich oxide layer. The SONOS device of claim 1, wherein the nitrogen-containing layer comprises a tantalum nitride layer, and the tantalum nitride layer has a thickness of 10-30 angstroms. The SONOS device of claim 1, wherein the nitrogen-containing layer comprises a layer of oxynitride, and the layer of ruthenium oxynitride has a thickness of from 10 to 30 angstroms. The SONOS element of claim 1, wherein the cerium-rich oxide layer has a thickness of less than 15 angstroms. For example, the SONOS device of claim 1 further comprises a second oxide layer disposed between the germanium-rich oxide layer and the polysilicon layer. A method of making a bismuth-oxide-nitride-oxide-germanium (SONOS) device, comprising: providing a substrate; Forming a first oxide layer on the substrate; forming a tantalum nitride layer on the first oxide layer; performing a first silane soak process; introducing ammonia gas and methane to form a rich lanthanum a tantalum nitride layer is disposed on the tantalum nitride layer; a nitrogen-containing layer is formed on the germanium-rich tantalum nitride layer; a germanium-rich oxide layer is formed on the nitrogen-containing layer; and a polysilicon layer is formed on the germanium-rich layer On the oxide layer. The method for fabricating a SONOS device according to Item 6 of the patent application further includes: performing an ammonia gas immersion process on the first oxide layer; and introducing ammonia gas and methane to form the tantalum nitride layer. The method of fabricating a SONOS device according to item 6 of the patent application further comprises performing a microwave plasma assisted chemical vapor deposition (microwave PECVD) process to form the tantalum nitride layer. The method for fabricating a SONOS device according to Item 6 of the patent application, further comprising: performing the first methane immersion process on the tantalum nitride layer in a plasma off state; and on plasma on (plasma on) In the state, ammonia gas and helium methane are introduced to form the germanium-rich tantalum nitride layer. A method of fabricating a SONOS device according to item 6 of the patent application, wherein the nitrogen-containing layer comprises a tantalum nitride layer. A method for fabricating a SONOS device according to item 6 of the patent application, wherein the nitrogen-containing layer Contains a layer of oxynitride. The method for fabricating a SONOS device according to the eleventh application patent scope further includes: performing a second methane methane immersion process on the tantalum nitride layer in a plasma closed state; and introducing ammonia gas and oxygen gas in a plasma open state; And methane is formed to form the ruthenium oxynitride layer. A method of fabricating a SONOS device according to claim 6 wherein the forming of the polysilicon layer further comprises forming a second oxide layer on the germanium-rich oxide layer. The method for fabricating a SONOS device according to Item 6 of the patent application, wherein the first methane soaking process further comprises pre-cleaning with helium gas, and the pre-cleaning temperature is higher than 300 degrees Celsius. The method for fabricating a SONOS device according to claim 6 of the patent application, wherein the first methane soaking process is performed in an same chamber tool in an atmospheric or sub-atmospheric environment. . A method of fabricating a germanium-oxide-nitride-oxide-germanium (SONOS) device, comprising: providing a substrate; forming a first oxide layer on the substrate; forming a tantalum nitride layer on the first oxide layer a first silane soak process; introducing ammonia gas, oxygen and helium methane to form a ruthenium-rich ruthenium oxide layer disposed on the tantalum nitride layer Forming a nitrogen-containing layer on the cerium-rich cerium oxide layer; forming a cerium-rich oxide layer on the nitrogen-containing layer; and forming a polysilicon layer on the cerium-rich oxide layer. The method for fabricating a SONOS device according to claim 16 of the patent application scope, further comprising: performing the first methane immersion process on the tantalum nitride layer in a plasma closed state; and introducing ammonia gas and oxygen gas in a plasma open state; And methane to form the yttrium-rich yttrium oxide layer. A germanium-oxide-nitride-oxide-germanium (SONOS) device comprising: a substrate; a first oxide layer disposed on the substrate; a tantalum nitride layer disposed on the first germanium oxide layer; An yttrium-rich yttrium oxide layer is disposed on the tantalum nitride layer; a nitrogen-containing layer is disposed on the yttrium-rich yttrium oxide layer; a silicon-rich oxide layer is disposed on the nitrogen-containing layer; And a polysilicon layer is disposed on the germanium-rich oxide layer.