CN105047720B - Silicon-on-insulator RF switching devices structure - Google Patents

Abstract

The invention provides a silicon-on-insulator radio frequency switching device structure, comprising: a buried oxide layer as an insulating layer, a device region and a body region arranged in an active layer on the buried oxide layer; a device region is formed in the device region a channel region, a source region and a drain region; and wherein, a gate oxide layer and a gate polysilicon are sequentially arranged on the channel region; at the first end in the extending direction of the gate polysilicon, the gate polysilicon passes through The hole is connected to the gate metal wiring; at the second end in the extending direction of the gate polysilicon, the first heavily doped region which is in the same layer as the channel region and adjacent to the channel region is connected to the metal connection wiring through the via hole The first end; the second end of the metal connection wiring is connected to the second heavily doped region through a through hole; it is in the same layer as the second heavily doped region and is in the same layer as and adjacent to the lightly doped region; in the lightly doped region The connection polysilicon is arranged on the doped region; the connection polysilicon is connected to the gate metal wiring through the through hole.

Description

Silicon-on-insulator RF switching device structure

technical field

The invention relates to the field of semiconductor manufacturing, and more specifically, the invention relates to a silicon-on-insulator radio frequency switch device structure.

Background technique

Silicon is the most widely used primary raw material in the semiconductor industry, and most chips are made of silicon wafers. Silicon-on-insulator (SOI, Silicon-on-insulator) is a special silicon chip, the main feature of its structure is to insert an insulating layer (buried oxide layer) between the active layer and the substrate layer to isolate the active layer and The electrical connection between substrates, this structural feature brings many advantages such as small parasitic effects, fast speed, low power consumption, high integration, and strong radiation resistance to silicon-on-insulator devices.

Today, silicon-on-insulator technology has been used to fabricate switching devices. In general, for specific electronic circuit applications, linearity is an important specification for silicon-on-insulator RF switching devices. However, for some specific applications, the isolation performance and linearity of existing silicon-on-insulator RF switching devices cannot meet the requirements. Therefore, it is desired to provide a device structure that can effectively improve the isolation performance and linearity of silicon-on-insulator radio frequency switching devices.

Contents of the invention

The technical problem to be solved by the present invention is to provide a device structure capable of effectively improving the isolation performance and linearity of silicon-on-insulator radio frequency switching devices in view of the above-mentioned defects in the prior art.

In order to achieve the above technical objectives, according to the present invention, a silicon-on-insulator radio frequency switching device structure is provided, including: a buried oxide layer as an insulating layer, a device region and a body arranged in the active layer on the buried oxide layer region; a channel region, a source region and a drain region are formed in the device region; and, wherein, a gate oxide layer and a gate polysilicon are sequentially arranged on the channel region; the first in the extending direction of the gate polysilicon At one end, the gate polysilicon is connected to the gate metal wiring through a via hole; at the second end in the extending direction of the gate polysilicon, the first heavily doped region that is in the same layer as the channel region and adjacent to the channel region passes through The through hole is connected to the first end of the metal connection wiring; the second end of the metal connection wiring is connected to the second heavily doped region through the through hole; it is in the same layer as the second heavily doped region and is in the same layer and adjacent to the ground The lightly doped region is arranged; the connection polysilicon is arranged on the lightly doped region; the connection polysilicon is connected to the gate metal wiring through the through hole.

Preferably, the lightly doped region, the first heavily doped region and the second heavily doped region have the same doping type.

Preferably, the doping type of the lightly doped region, the first heavily doped region and the second heavily doped region is P-type doping.

Preferably, the doping type of the connecting polysilicon is opposite to that of the lightly doped region, the first heavily doped region and the second heavily doped region.

Preferably, sidewalls are arranged on the side where the polysilicon is connected.

Preferably, the sidewall is above the second heavily doped region.

Preferably, the silicon layer in the body region, the channel region, the source region and the drain region are surrounded by isolation regions.

Preferably, the isolation regions are shallow trench isolations.

Preferably, the buried oxide layer is arranged on the silicon base layer.

Description of drawings

A more complete understanding of the invention, and its accompanying advantages and features, will be more readily understood by reference to the following detailed description, taken in conjunction with the accompanying drawings, in which:

Fig. 1 schematically shows a top view of the structure of a silicon-on-insulator radio frequency switching device according to a preferred embodiment of the present invention.

Fig. 2 schematically shows a schematic cross-sectional view of a silicon-on-insulator radio frequency switching device structure along line A-A' of Fig. 1 according to a preferred embodiment of the present invention.

Fig. 3 schematically shows a schematic cross-sectional view of a silicon-on-insulator radio frequency switching device structure along line B-B' in Fig. 1 according to a preferred embodiment of the present invention.

It should be noted that the accompanying drawings are used to illustrate the present invention, but not to limit the present invention. Note that drawings showing structures may not be drawn to scale. And, in the drawings, the same or similar elements are marked with the same or similar symbols.

Detailed ways

In order to make the content of the present invention clearer and easier to understand, the content of the present invention will be described in detail below in conjunction with specific embodiments and accompanying drawings.

Fig. 1 schematically shows a top view of the structure of a silicon-on-insulator radio frequency switching device according to a preferred embodiment of the present invention. Fig. 2 schematically shows a schematic cross-sectional view of a silicon-on-insulator radio frequency switching device structure along line A-A' of Fig. 1 according to a preferred embodiment of the present invention. Fig. 3 schematically shows a schematic cross-sectional view of a silicon-on-insulator radio frequency switching device structure along line B-B' in Fig. 1 according to a preferred embodiment of the present invention.

As shown in FIG. 1 , FIG. 2 and FIG. 3 , the silicon-on-insulator radio frequency switching device structure according to a preferred embodiment of the present invention includes: a buried oxide layer 60 as an insulating layer, an active layer disposed on the buried oxide layer 60 The device region and body region in .

Wherein, a channel region 30 , a source region 31 and a drain region 32 are formed in the device region; moreover, a gate oxide layer 41 and a gate polysilicon 10 are sequentially arranged on the channel region 30 .

At the first end in the extending direction of the gate polysilicon 10, the gate polysilicon 10 is connected to the gate metal wiring 21 through a via hole; at the second end in the extending direction of the gate polysilicon 10, it is at the same level as the channel region 30 The first heavily doped region 91 adjacent to the channel region 30 is connected to the first end of the metal connection wiring 24 through a via hole; the second end of the metal connection wiring 24 is connected to the second heavily doped region 92 through a via hole ; be in the same layer as the second heavily doped region 92 and be in the same layer and adjacently arranged with the lightly doped region 34 ; the connection polysilicon 80 is arranged on the lightly doped region 34 ; the connection polysilicon 80 is connected to the gate through a via hole pole metal wiring 21 .

Therefore, in the silicon-on-insulator radio frequency switching device structure according to the preferred embodiment of the present invention, as shown by the dotted line diode in FIG. Isolation performance and linearity of RF switching devices on silicon.

The lightly doped region 34 , the first heavily doped region 91 and the second heavily doped region 92 have the same doping type, such as P-type doping.

Preferably, the doping type of the connecting polysilicon 80 is opposite to that of the lightly doped region 34 , the first heavily doped region 91 and the second heavily doped region 92 , such as N-type doping.

Preferably, a sidewall 81 is arranged on the side connecting the polysilicon 80 ; moreover, the sidewall 81 is above the second heavily doped region 92 .

Further, specifically, the silicon layer in the body region 200 , the channel region 30 , the source region 31 and the drain region 32 are surrounded by the isolation region 50 to be separated from other devices.

Wherein, specifically, for example, the isolation region 50 is a shallow trench isolation.

Wherein, specifically, as shown in FIGS. 2 and 3 , the buried oxide layer 60 is disposed on the silicon base layer 70 . The silicon base layer 70 provides mechanical support for the above buried oxide layer 60 and the device structure on the buried oxide layer 60 .

For example, as shown in FIG. 3 , the lightly doped region 34 and the second heavily doped region 92 are arranged in the shallow trench isolation 51 to be separated from other structures.

In addition, it should be noted that, unless otherwise specified or pointed out, the terms “first”, “second”, “third” and other descriptions in the specification are only used to distinguish each component, element, step, etc. in the specification, and It is not used to represent the logical relationship or sequential relationship between various components, elements, and steps.

It can be understood that although the present invention has been disclosed above with preferred embodiments, the above embodiments are not intended to limit the present invention. For any person skilled in the art, without departing from the scope of the technical solution of the present invention, the technical content disclosed above can be used to make many possible changes and modifications to the technical solution of the present invention, or be modified to be equivalent to equivalent changes. Example. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, which do not deviate from the technical solution of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims (9)

1. A silicon-on-insulator radio frequency switching device structure is characterized in that comprising: a buried oxide layer as an insulating layer, a device region and a body region arranged in an active layer on the buried oxide layer; formed in the device region There are a channel region, a source region and a drain region; and, wherein, a gate oxide layer and a gate polysilicon are sequentially arranged on the channel region; at the first end in the extending direction of the gate polysilicon, the gate polysilicon passes through The via hole is connected to the gate metal wiring; at the second end in the extending direction of the gate polysilicon, the first heavily doped region which is in the same layer as the channel region and is adjacent to the channel region is connected to the metal connection wiring through the via hole The first end of the metal connection wiring is connected to the second heavily doped region through a via hole; the second heavily doped region is in the same layer and the lightly doped region is arranged adjacently; the lightly doped region is arranged on the lightly doped region There is connection polysilicon; the connection polysilicon is connected to the gate metal wiring through a through hole; the doping type of the connection polysilicon is opposite to that of the lightly doped region, and a diode is formed between the lightly doped region and the connection polysilicon. 2. The silicon-on-insulator radio frequency switching device structure according to claim 1, wherein the lightly doped region, the first heavily doped region and the second heavily doped region have the same doping type. 3. The silicon-on-insulator radio frequency switching device structure according to claim 1 or 2, wherein the doping type of the lightly doped region, the first heavily doped region and the second heavily doped region is P-type doping . 4. The silicon-on-insulator radio frequency switching device structure according to claim 1 or 2, characterized in that the doping type of the polysilicon is connected to the doping type of the lightly doped region, the first heavily doped region and the second heavily doped region Miscellaneous types are the opposite. 5. The silicon-on-insulator radio frequency switching device structure according to claim 1 or 2, characterized in that side walls are arranged on the side connected to the polysilicon. 6 . The silicon-on-insulator radio frequency switching device structure according to claim 5 , wherein the sidewall is above the second heavily doped region. 7. The silicon-on-insulator radio frequency switching device structure according to claim 1 or 2, characterized in that the silicon layer in the body region, the channel region, the source region and the drain region are surrounded by isolation regions. 8. The silicon-on-insulator radio frequency switching device structure according to claim 7, wherein the isolation region is a shallow trench isolation. 9. The silicon-on-insulator radio frequency switching device structure according to claim 1 or 2, characterized in that the buried oxide layer is arranged on the silicon base layer.