阅读说明：本技术 一种栅控双极-场效应复合氮化镓横向双扩散金属氧化物半导体晶体管 (gate-controlled bipolar-field effect composite gallium nitride transverse double-diffusion metal oxide semiconductor transistor ) 是由 段宝兴 董自明 智常乐 张一攀 杨银堂 于 2019-08-14 设计创作，主要内容包括：本发明公开了一种栅控双极-场效应复合氮化镓横向双扩散金属氧化物半导体晶体管。该器件通过采用基区与栅极相连的电极连接方式,代替传统的氮化镓LDMOS中基区与源极短接的电极连接方式。工作在关态时,器件的耐压特性与传统的氮化镓LDMOS的一致,器件的栅极,基区和源极接地,漏极接高电位；工作在开态时,寄生的双极型晶体管开启,提供了一个新的导电通道,沟道同样能正常开启进行导电。该结构采用栅极与基区相连的电极连接方式,与采用传统的氮化镓LDMOS器件相比,在保证器件具有相同击穿电压的同时,大幅度提高器件的导通电流,极大改善氮化镓晶体管的导通性能。(the invention discloses a grid-controlled bipolar-field effect composite gallium nitride transverse double-diffusion metal oxide semiconductor transistor. The device replaces the traditional electrode connection mode of short circuit between the base region and the source electrode in the gallium nitride LDMOS by adopting the electrode connection mode of connecting the base region and the grid electrode. When the device works in an off state, the voltage-resistant characteristic of the device is consistent with that of the traditional gallium nitride LDMOS, the grid electrode, the base region and the source electrode of the device are grounded, and the drain electrode is connected with a high potential; when the bipolar transistor works in an on state, the parasitic bipolar transistor is turned on, a new conductive channel is provided, and the channel can be also normally turned on to conduct electricity. The structure adopts an electrode connection mode that the grid electrode is connected with the base region, and compared with the traditional gallium nitride LDMOS device, the structure ensures that the device has the same breakdown voltage, greatly improves the conduction current of the device and greatly improves the conduction performance of a gallium nitride transistor.)

1. A gated bipolar-field effect composite gan ldmos transistor comprising:

A substrate of silicon material;

generating an epitaxial layer of gallium nitride material on the substrate;

A base region and a drift region formed on the epitaxial layer;

A source region and a corresponding channel are formed in the middle area of the upper part of the base region;

a drain region formed on one end of the drift region far away from the base region;

The gate insulating layer covers the channel and the part of the drift region adjacent to the channel;

The grid electrode is positioned on the surface of the grid insulation layer above the channel;

The base electrode is positioned on the surface of the base region far away from one end of the channel;

The source electrode is positioned on the surface of the source region;

The drain electrode is positioned on the surface of the drain region;

The base electrode is isolated from the source electrode and is electrically connected with the grid electrode, and the requirements of: when the grid is connected with voltage, the voltage obtained by the base region enables the parasitic bipolar transistor of the device to be started.

2. the gated bipolar-field effect composite gallium nitride lateral double diffused metal oxide semiconductor transistor of claim 1, wherein: the connecting material between the base electrode and the grid electrode is a conductor material, so that the base electrode and the grid electrode are consistent in potential when the grid electrode is connected with voltage.

3. the gated bipolar-field effect composite gallium nitride lateral double diffused metal oxide semiconductor transistor of claim 2, wherein: the conductor material is copper or aluminum.

4. the gated bipolar-field effect composite gallium nitride lateral double diffused metal oxide semiconductor transistor of claim 1, wherein: the connecting material between the base electrode and the grid electrode is a semiconductor material, so that the potential of the base electrode is greater than the potential of the grid electrode when the base electrode is connected with voltage, and the potential of the grid electrode is greater than the potential of the base electrode when the grid electrode is connected with voltage.

5. the gated bipolar-field effect composite gallium nitride lateral double diffused metal oxide semiconductor transistor of claim 4, wherein: the semiconductor material is semi-insulating polysilicon.

6. The gated bipolar-field effect composite gallium nitride lateral double diffused metal oxide semiconductor transistor of claim 1, wherein: the silicon substrate is an undoped monocrystalline silicon material.

7. The gated bipolar-field effect composite gallium nitride lateral double diffused metal oxide semiconductor transistor of claim 1, wherein: the length of the base region is 4-6 microns, the thickness of the base region is 1-3 microns, and the magnesium doping concentration of the base region is 1 x 1018 cm-3-2 x 1018 cm-3; the length of the source region is 1-2 mu m, and the silicon doping concentration of the source region is 1 x 1018 cm-3-2 x 1018 cm-3; the length of the drain region is 1-2 mu m, and the silicon doping concentration of the drain region is 1 x 1018 cm-3-2 x 1018 cm-3; the length of the drift region is 10-90 μm, the thickness of the drift region is 1-3 μm, and the silicon doping concentration of the drift region is 1 × 1016 cm-3-2 × 1016 cm-3.

8. The gated bipolar-field effect composite gallium nitride lateral double diffused metal oxide semiconductor transistor of claim 1, wherein: the source region and the source electrode are in ohmic contact, the drain region and the drain electrode are in Schottky contact, and the base electrode and the base region are in ohmic contact.

9. The gated bipolar-field effect composite gallium nitride lateral double diffused metal oxide semiconductor transistor of claim 1, wherein: the thickness of the epitaxial layer is 10-50 mu m.

Technical Field

The invention relates to the technical field of semiconductor power devices, in particular to a transverse double-diffusion transistor.

background

Compared with the traditional narrow-bandgap semiconductor, the wide-bandgap gallium nitride has more excellent physical properties, such as high forbidden bandwidth, high breakdown electric field, high electron mobility, acid and alkali resistance and the like, is suitable for preparing power electronic devices working under the conditions of high temperature, high pressure, high frequency and the like, and has wide prospects in the aspects of military affairs, civil engineering and the like. The growth of gallium nitride material has already had a relatively mature solution, and the advantage of HVPE can be utilized to prepare a high-quality thick-film gallium nitride epitaxial layer. Therefore, power electronic devices made of gallium nitride materials have become a popular research field in the semiconductor field.

LDMOS is a very important structure in the development of power MOS field effect transistors and is widely used because it is more compatible with CMOS processes. In order to realize high voltage and large current, the LDMOS layout area is large, the chip cost is high, and the compromise between the on-resistance and the breakdown voltage is the main defect.

the traditional LDMOS does not pay enough attention to a parasitic bipolar transistor, and adopts a short-circuit electrode connection mode between a base region and a source region. In an open state, the parasitic bipolar transistor cannot be opened because the base region is in short circuit with the source region, and the device can only conduct electricity in a normally opened channel.

Disclosure of Invention

the invention provides a grid-controlled bipolar-field effect composite gallium nitride transverse double-diffusion metal oxide semiconductor transistor, aiming at further effectively increasing the on-current of a device (reducing the on-resistance of the device) on the premise of meeting the voltage withstanding requirement.

the technical scheme of the invention is as follows:

A gated bipolar-field effect composite gallium nitride lateral double diffused metal oxide semiconductor transistor comprising:

A substrate of silicon material;

Generating an epitaxial layer of gallium nitride material on the substrate;

A base region and a drift region formed on the epitaxial layer;

a source region and a corresponding channel are formed in the middle area of the upper part of the base region;

A drain region formed on one end of the drift region far away from the base region;

A gate insulating layer covering the channel and a part of the drift region adjacent to the channel (while a part close to the drain region mainly serves as a passivation layer);

The grid electrode is positioned on the surface of the grid insulation layer above the channel;

the base electrode is positioned on the surface of the base region far away from one end of the channel;

the source electrode is positioned on the surface of the source region;

the drain electrode is positioned on the surface of the drain region;

the base electrode is isolated from the source electrode and is electrically connected with the grid electrode, and the requirements of: when the grid is connected with voltage, the voltage obtained by the base region enables the parasitic bipolar transistor of the device to be started.

The connecting material between the base and the gate can be a conductor material, so that the base and the gate are in the same potential when the gate is connected with voltage. The conductor material is preferably copper or aluminum.

the connecting material between the base electrode and the grid electrode can also be a semiconductor material, so that the potential of the base electrode is greater than the potential of the grid electrode when the base electrode is connected with voltage, and the potential of the grid electrode is greater than the potential of the base electrode when the grid electrode is connected with voltage. The semiconductor material is preferably semi-insulating polysilicon.

The silicon substrate is preferably an undoped single crystal silicon material.

The parameters of each region of the device are optimized as follows:

the length of the base region is 4-6 microns, the thickness of the base region is 1-3 microns, and the magnesium doping concentration of the base region is 1 x 1018 cm-3-2 x 1018 cm-3; the length of the source region is 1-2 mu m, and the silicon doping concentration of the source region is 1 x 1018 cm-3-2 x 1018 cm-3; the length of the drain region is 1-2 mu m, and the silicon doping concentration of the drain region is 1 x 1018 cm-3-2 x 1018 cm-3; the length of the drift region is 10-90 μm, the thickness of the drift region is 1-3 μm, and the silicon doping concentration of the drift region is 1 × 1016 cm-3-2 × 1016 cm-3.

The thickness of the GaN epitaxial layer is 10-50 μm.

The source region and the source electrode are in ohmic contact, the drain region and the drain electrode are in Schottky contact, and the base electrode and the base region are in ohmic contact.

the technical scheme of the invention has the following beneficial effects:

according to the grid-controlled bipolar-field effect composite gallium nitride transverse double-diffusion metal oxide semiconductor transistor, a gallium nitride material is applied, and a traditional electrode connection mode of short circuit between a base region and a source region is changed into an electrode connection mode of connecting a base region electrode and a grid electrode. When the device works in an off state, the breakdown characteristic of the device is consistent with that of a gallium nitride device. The grid electrode, the base region and the source electrode of the device are grounded, and the drain electrode is connected with a high potential, so that a parasitic bipolar transistor does not work among the source region, the base region and the drift region when the device works in an off state, secondary breakdown is prevented, and the breakdown characteristic of the device is the same as that of the traditional device. When the bipolar transistor works in an on state, the grid electrode is connected with the base region electrode, and when the grid electrode is connected with grid voltage, the base region is also connected with certain voltage, so that the parasitic bipolar transistor of the device is started, and a new conductive channel is provided; at the same time, the channel of the device can also be normally turned on for conduction.

Compared with the traditional gallium nitride LDMOS device, the invention ensures that the device has the same breakdown voltage, greatly improves the conduction current of the device and greatly improves the conduction performance of the gallium nitride transistor.

drawings

fig. 1 is a schematic structural diagram of a gated bipolar-field effect composite gan ldmos transistor according to the present invention.

fig. 2 illustrates a conductive path based on the structure shown in fig. 1. Wherein, A is a conductive channel formed by a channel, and B is a conductive channel formed by starting a parasitic bipolar transistor.

The reference numbers illustrate:

1-a silicon substrate; 2-an epitaxial layer of gallium nitride; 3-base region; a 4-source region; 5-a drain region; 6-a drift region; a 7-source electrode; 8-a grid; 9-a drain electrode; a 10-base.

Detailed Description

as shown in fig. 1, the gated bipolar-field effect composite gan ldmos transistor of the present embodiment includes:

the silicon substrate 1 adopts undoped monocrystalline silicon material, so that large-size gallium nitride can grow on the silicon substrate conveniently;

Growing a gallium nitride epitaxial layer 2 on a silicon substrate 1, wherein the thickness of the gallium nitride epitaxial layer is 10-50 mu m;

forming a P-type base region 3 and a drift region 6 on the gallium nitride epitaxial layer 2, and forming an active region on the surface of the device;

Forming a gate insulating layer on the active region, and forming a gate electrode 8 over the gate insulating layer;

Forming a source region 4 on the base region and simultaneously forming a channel;

forming a drain region 5 on the drift region;

The length of the base region is 4-6 microns, the thickness of the base region is 1-3 microns, and the magnesium doping concentration of the base region is 1 x 1018 cm-3-2 x 1018 cm-3; the length of the source region is 1-2 mu m, and the silicon doping concentration of the source region is 1 x 1018 cm-3-2 x 1018 cm-3; the length of the drain region is 1-2 mu m, and the silicon doping concentration of the drain region is 1 x 1018 cm-3-2 x 1018 cm-3; the length of the drift region is 10-90 mu m, the thickness of the drift region is 1-3 mu m, and the silicon doping concentration of the drift region is 1 x 1016 cm-3-2 x 1016 cm-3;

Respectively generating a base electrode 10, a source electrode 7 and a drain electrode 9 on the base region 3, the source region 4 and the drain region 5; the source region and the source electrode are in ohmic contact, the drain region and the drain electrode are in Schottky contact, and the base electrode and the base region are in ohmic contact.

the base 10 of the device is connected to the gate 8. Specifically, the method comprises the following steps:

the connecting material between the base region 2 and the grid 8 can be a conductor material (such as copper and aluminum), and when the grid 8 is connected with a voltage, the base region and the grid 8 are in consistent potential.

The connecting material between the base region 2 and the gate 8 may be a resistive material (e.g., semi-insulating polysilicon, etc.). When the base region 2 is connected with voltage, the potential of the base region 2 is greater than that of the grid 8; when the grid 8 is connected with voltage, the potential of the grid 8 is larger than that of the base region 2.

It should be noted that the grid electrode and the base electrode common connection leading-out terminal shown in the drawing is a topological schematic, and in an actual product, the base electrode and the grid electrode are connected and then led out, and the base electrode and the grid electrode can be directly led out from the base electrode or directly led out from the grid electrode. There is a difference in the potential of the gate electrode and the base electrode due to the difference in the resistance between the base electrode and the gate electrode and the position of the extraction electrode.

when the gate-controlled bipolar-field effect composite gallium nitride transverse double-diffusion metal oxide semiconductor transistor works in an off state, the breakdown characteristic of the device is consistent with that of a gallium nitride device. The grid electrode, the base region and the source electrode of the device are grounded, and the drain electrode is connected with a high potential, so that a parasitic bipolar transistor does not work among the source region, the base region and the drift region when the device works in an off state, secondary breakdown is prevented, and the breakdown characteristic of the device is the same as that of the traditional device. When the grid electrode is in an on state, the grid electrode is connected with the base region electrode, and when the grid electrode is connected with grid voltage, the base region is also connected with certain voltage. A new conductive channel B is added by starting a parasitic bipolar transistor among the source region, the base region and the drift region. At the same time, the channel of the device can also be normally turned on for conduction. The on-state current of the device is greatly increased, and the on-state resistance of the device is greatly reduced.

Compared with the gallium nitride device, the conduction current density of the invention is greatly improved, and the conduction current density of the two devices is improved by one to three orders of magnitude under the condition that the drift regions of the two devices are the same and the breakdown voltage of the two devices is the same.

Of course, the LDMOS of the present invention may also be a P-channel LDMOS, and the structure thereof is the same as that of an N-channel LDMOS, which is not described herein again.

the above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, many modifications and substitutions can be made without departing from the technical principle of the present invention, and these modifications and substitutions also fall into the protection scope of the present invention.