阅读说明：本技术 一种具有低饱和电流特性的氮化镓功率器件 (Gallium nitride power device with low saturation current characteristic ) 是由 张龙 崔永久 马杰 骆敏 刘培港 王肖娜 孙伟锋 时龙兴 于 2021-08-31 设计创作，主要内容包括：本发明是一种具有低饱和电流特性的氮化镓功率器件,包括：P型硅衬底上方设有氮化镓缓冲层、铝镓氮势垒层、源极和漏极,作为连接铝镓氮势垒层两端至外围的输入\输出,源极与铝镓氮势垒层左端形成欧姆接触,漏极金属和铝镓氮势垒层右端形成欧姆接触,铝镓氮势垒层上方设有P型氮化镓层,P型氮化镓层上方设有栅极金属连接铝镓氮势垒层至结构外围的输入\输出,栅极金属和P型氮化镓层形成肖特基接触,P型氮化镓层和栅极在源漏极之间相对距离源极较近,相对距离漏极较远,铝镓氮势垒层上方漏极和P型氮化镓之间设有氮化物钝化层,本发明结构可以有效降低氮化镓功率器件的饱和电流,提高整个器件结构的安全性和可靠性。(The invention relates to a gallium nitride power device with low saturation current characteristic, which comprises: a gallium nitride buffer layer and an AlGaN barrier layer are arranged above the P-type silicon substrate, the structure of the invention can effectively reduce the saturation current of a gallium nitride power device and improve the safety and reliability of the structure of the whole device.)

1. A gallium nitride power device having low saturation current characteristics, comprising: the device comprises a P-type silicon substrate (1), wherein a gallium nitride buffer layer (2) is arranged above the P-type silicon substrate (1), an aluminum gallium nitrogen barrier layer (3) is arranged above the gallium nitride buffer layer (2), metals serving as a source electrode (6) and a drain electrode (7) are respectively arranged at two ends above the aluminum gallium nitrogen barrier layer (3) and used as input/output for connecting two ends of the aluminum gallium nitrogen barrier layer (3) to the periphery, the metal of the source electrode (6) and the left end of the aluminum gallium nitrogen barrier layer (3) form ohmic contact, and the metal of the drain electrode (7) and the right end of the aluminum gallium nitrogen barrier layer (3) form ohmic contact; be equipped with P type gallium nitride layer (9) above aluminium gallium nitride barrier layer (3), P type gallium nitride layer (9) top is equipped with grid (8) metal connection aluminium gallium nitride barrier layer to structure outlying input \ output, grid (8) metal and P type gallium nitride layer (9) form the schottky contact, P type gallium nitride layer (9) and grid (8) are nearer apart from source electrode (6) relatively between source drain electrode, relative distance drain electrode (7) are far away, be equipped with nitride passivation layer (4) between aluminium gallium nitride barrier layer (3) top drain electrode (7) and P type gallium nitride (9), be equipped with nitride passivation layer (5) between source electrode (6) and P type gallium nitride (9), be equipped with metal field plate (10) on nitride passivation layer (4).

2. Gallium nitride power device with low saturation current characteristics according to claim 1, characterized in that said metal field plate (10) is between the drain (7) and the gate (8) and covers the right end portion area of the P-type gallium nitride layer (9).

3. The GaN power device with low saturation current characteristic as claimed in claim 2, wherein the metal field plate (10) is relatively close to the gate (8) and the P-type GaN layer (9) and relatively far from the drain (7).

4. Gallium nitride power device with low saturation current characteristics according to claim 1, characterized in that the length of the P-type gallium nitride layer (9) is extended to the right with respect to conventional gallium nitride devices.

5. Gallium nitride power device with low saturation current characteristics according to claim 1, characterized in that the length of the metal field plate (10) on the nitride passivation layer (4) is extended to the left with respect to the conventional structure and covers the right end portion region of the P-type gallium nitride layer (9).

Technical Field

The invention mainly relates to the technical field of power integrated circuits, in particular to the power integrated circuit which is particularly suitable for the power control processing fields of switching power supplies, motor control, automobile electronic systems, household appliances and the like.

Background

The requirements of the semiconductor industry for power devices are increasing nowadays, mainly including high power density, low on-resistance, high reliability, high frequency, small volume and strong radiation resistance. However, the performance of silicon-based power devices mainly including metal oxide semiconductor field effect transistors and insulated gate bipolar transistors approaches the theoretical limit of materials, and the higher requirements of next-generation power electronic systems on power devices cannot be met, so that the breakthrough of the silicon limit is of great importance. Gallium nitride materials have been used as a representative of wide bandgap semiconductor materials, and in the last two decades, great research progress has been made in the aspects of material preparation, theoretical research, power device fabrication, power integrated circuit design, and the like. It is expected that gan power devices will necessarily occupy an important place in the future power electronics market.

Compared with the traditional semiconductor silicon, the third-generation semiconductor material gallium nitride has the outstanding advantages of wide forbidden bandwidth, high electron saturation drift velocity, high critical breakdown electric field, good chemical performance and the like, and meanwhile, a two-dimensional electron gas heterojunction channel with high concentration and high mobility is formed on an interface by a heterojunction formed by the gallium nitride material and materials such as aluminum gallium nitrogen and the like, so that the gallium nitride is an ideal semiconductor material in the application occasions of high power, high temperature, high frequency and radiation resistance.

The gallium nitride high electron mobility transistor power device has the advantages of high current density, fast switching speed, low on-resistance and the like; however, the saturation current of the gan power device is too large, when the load is short-circuited, the working voltage is directly applied to the two ends of the drain and the source, so that the gan device generates a large current, and further the device generates heat, if the device fails due to long time, even the safety and reliability problems of the system cause great inconvenience to the practical application.

The invention provides a novel gallium nitride power device structure aiming at the problem of larger saturation current of a gallium nitride power device, effectively reduces the saturation current of the gallium nitride power device, further improves the short-circuit resistance of the gallium nitride power device, and finally improves the practical performance of the whole device structure.

Disclosure of Invention

The technical problem is as follows: aiming at the problems, the invention provides the gallium nitride power device with the characteristic of low saturation current.

The technical scheme is as follows: the invention relates to a gallium nitride power device with low saturation current characteristic, which comprises: the device comprises a P-type silicon substrate, wherein a gallium nitride buffer layer is arranged above the P-type silicon substrate, an aluminum gallium nitrogen barrier layer is arranged above the gallium nitride buffer layer, metals are respectively arranged at two ends above the aluminum gallium nitrogen barrier layer and are used as a source electrode and a drain electrode and are used as input/output for connecting two ends of the aluminum gallium nitrogen barrier layer to the periphery, the source electrode metal and the left end of the aluminum gallium nitrogen barrier layer form ohmic contact, and the drain electrode metal and the right end of the aluminum gallium nitrogen barrier layer form ohmic contact; be equipped with the P type gallium nitride layer above the aluminium gallium nitrogen barrier layer, P type gallium nitride layer top is equipped with the grid metal and connects aluminium gallium nitrogen barrier layer to the peripheral input of structure \ output, grid metal and P type gallium nitride layer form the schottky contact, P type gallium nitride layer and grid are nearer at the relative distance source electrode between the source drain electrode, the relative distance drain electrode is far away, be equipped with the nitride passivation layer between aluminium gallium nitrogen barrier layer top drain electrode and the P type gallium nitride, be equipped with the nitride passivation layer between source electrode and the P type gallium nitride, be equipped with the metal field plate on the nitride passivation layer.

The metal field plate is arranged between the drain electrode and the grid electrode and covers the right end part region of the P-type gallium nitride layer.

The metal field plate is relatively close to the grid and the P-type gallium nitride layer and relatively far from the drain electrode.

The length of the P-type gallium nitride layer is prolonged to the right compared with the traditional gallium nitride device.

The length of the metal field plate on the nitride passivation layer is prolonged to the left compared with the traditional structure, and the metal field plate covers the right end part region of the P-type gallium nitride layer.

Has the advantages that: compared with the prior art, the invention has the following advantages:

in the conventional scheme, in order to improve the short-circuit resistance of the gallium nitride power device, an ultra-high speed detection circuit and a gate voltage clamping circuit are usually arranged outside the gallium nitride device to limit the short-circuit energy of the device.

On the basis of the traditional structure, the invention provides a new structure, the P-type gallium nitride layer is rightwards extended for a certain length, the length of the grid electrode is kept unchanged, and meanwhile, the metal field plate is leftwards extended for a certain length and covers the right end part area of the P-type gallium nitride layer. Under the forward conduction state of the device, the potential at the right end of the P-type gallium nitride layer is obviously reduced according to the potential superposition principle as the metal field plate is connected with 0 potential and extends leftwards; meanwhile, after the P-type gallium nitride layer is elongated, the depletion effect of the P-type gallium nitride layer on two-dimensional electron gas formed between the aluminum gallium nitrogen barrier layer and the gallium nitride buffer layer is intensified, so that the resistance of a channel is increased, the voltage at two ends of the channel is reduced, and the saturation current is correspondingly reduced according to ohm's law.

The structure of the invention can obviously reduce the saturation current of the device only by modifying the original gallium nitride power device on the P-type gallium nitride layer and the metal field plate structure, does not need additional external circuits and complex process steps, and is very economical and practical.

Drawings

Fig. 1 is a block diagram of a gallium nitride power device according to the present invention.

Fig. 2 shows the waveform diagrams of the surface potential distributions of the common gan power device and the gan power device with low saturation current of the present invention, where the cut positions are all at the position 0.05 μm below the gate from the gate metal, the gate-source voltage of both structures is 6v, and the drain-source voltage is 30 v.

Fig. 3 is a waveform diagram showing the electron concentration distribution of the cross section between the gan buffer layer and the algan barrier layer of the conventional gan power device and the gan power device with low saturation current according to the present invention, wherein the cut-off position is the side of the interface between the gan buffer layer and the algan barrier layer, which is close to the gan buffer layer.

Fig. 4 is an I-V waveform diagram of a general gallium nitride power device and a gallium nitride power device having a low saturation current characteristic according to the present invention.

The figure shows that: the P-type GaN-based semiconductor device comprises a P-type silicon substrate 1, a GaN buffer layer 2, an AlGaN barrier layer 3, a nitride passivation layer 4, a nitride passivation layer 5, a source electrode 6, a drain electrode 7, a grid electrode 8, a P-type GaN layer 9 and a metal field plate 10.

Detailed Description

The invention is described in detail below with reference to the figures:

the invention provides a gallium nitride power device with low saturation current characteristic, comprising: a P-type silicon substrate 1, a gallium nitride buffer layer 2 is arranged above the P-type silicon substrate 1, an aluminum gallium nitride barrier layer 3 is arranged above the gallium nitride buffer layer 2, metals are respectively arranged at two ends of the aluminum gallium nitride barrier layer 3 and are used as a source electrode 6 and a drain electrode 7 which are used as input/output for connecting two ends of the aluminum gallium nitride barrier layer 3 to the periphery, the metal of the source electrode 6 and the left end of the aluminum gallium nitride barrier layer 3 form ohmic contact, the metal of the drain electrode 7 and the right end of the aluminum gallium nitride barrier layer 3 form ohmic contact, a P-type gallium nitride layer 9 is arranged above the aluminum gallium nitride barrier layer 3, a grid electrode 8 is arranged above the P-type gallium nitride layer 9 and is connected with the aluminum gallium nitride barrier layer to the input/output of the periphery of the structure through the metal, the metal of the grid electrode 8 and the P-type gallium nitride layer 9 form Schottky contact, the P-type gallium nitride layer 9 and the grid electrode 8 are relatively close to the source electrode 6 and far from the drain electrode, a relatively far drain electrode 7 is arranged above the aluminum gallium nitride barrier layer 3, a nitride passivation layer 4 is arranged between the drain electrode 7 and the P-type gallium nitride 9, a nitride passivation layer 5 is arranged between the source electrode 6 and the P-type gallium nitride layer 9, a metal field plate 10 is arranged on the nitride passivation layer 4, the metal field plate 10 is arranged between the drain electrode 7 and the grid electrode 8 and covers the right end part region of the P-type gallium nitride layer 9, and the metal field plate 10 is relatively close to the grid electrode 8 and the P-type gallium nitride layer 9 and relatively far from the drain electrode 7.

In the gallium nitride power device, the P-type gallium nitride layer 9 is extended to the right, and the metal field plate 10 is extended to the left and covers the right end part region of the P-type gallium nitride layer 9.

The invention is further described below with reference to the accompanying drawings.

The working principle of the invention is as follows:

although the gallium nitride power device has the advantages of high current density, fast switching speed, low on-resistance and the like, the saturation current is too large, the short-circuit resistance is not strong, and the safety and the reliability of the device are poor.

In the conventional scheme, in order to improve the short-circuit resistance of the gallium nitride power device, an ultra-high speed detection circuit and a gate voltage clamping circuit are usually arranged outside the gallium nitride device to limit the short-circuit energy of the device.

On the basis of the traditional structure, the invention provides a new structure, the P-type gallium nitride layer is lengthened to the right by a certain length, the length of the grid electrode is kept unchanged, and meanwhile, the metal field plate is lengthened to the left by a certain length and covers the length of the right end part of the P-type gallium nitride layer. Under the forward conduction state of the device, the metal field plate is connected with 0 potential, extends leftwards along with the metal field plate and covers the right end of the P-type gallium nitride layer, and has a superposition effect on the potential of the region below the right end of the P-type gallium nitride layer according to a potential superposition principle, so that the potential of the right end of the P-type gallium nitride layer is obviously reduced, as shown in fig. 2, compared with a common structure, the partial region of the right end of the P-type gallium nitride layer of the patent structure is lower than the potential of the common structure, and when a grid is applied with voltage, the concentration of two-dimensional electron gas in the partial region is obviously reduced; meanwhile, after the P-type gallium nitride layer is elongated, the depletion length of the P-type gallium nitride layer to two-dimensional electron gas formed between the aluminum gallium nitride barrier layer and the gallium nitride buffer layer is prolonged, so that the channel resistance of the right end of the P-type gallium nitride layer towards the left part is increased, the channel resistance of the right end of the P-type gallium nitride layer towards the right part is unchanged, the voltage between the drain and the source is unchanged, and the saturation current is correspondingly reduced according to ohm's law; as shown in fig. 3, compared with the conventional structure, the electron concentration under the P-type gan layer of the structure of the present invention is significantly reduced, and the electron concentration is generally lower, so that the saturation current is significantly reduced compared with the conventional structure. As shown in fig. 4, the saturation current of the gan device with low saturation current characteristic of the structure of the present patent is reduced by about 27.5% compared with the gan device with the conventional structure.

Through lengthening the length of the P-type gallium nitride layer and the metal field plate, the voltage from the right end of the P-type gallium nitride layer to the source electrode is reduced, the resistance of two-dimensional electron gas is improved, the effect of reducing the saturation current of the gallium nitride device is achieved, the safety and the reliability of the device are further improved, and the application range of the gallium nitride device is expanded.