阅读说明：本技术 一种快恢复二极管 (Fast recovery diode ) 是由 王源政 金银萍 杭圣桥 郁怀东 于 2019-10-28 设计创作，主要内容包括：本发明公开了半导体功率器件领域内的一种快恢复二极管。该种快恢复二极管包括N+型硅单晶衬底、N-型外延层、P+型块和P-型主结,P+型块具有若干个,N-型外延层设置于N+型硅单晶衬底上方,P-型主结设置于N-型外延层内上方,P+型块设置于N+型硅单晶衬底和N-型外延层之间,P-型主结上方设置有正面金属层,N+型硅单晶衬底下方设置有背面金属层。该种快恢复二极管具有极短的反向恢复时间、快速开通和关断能力,同时具有极低的电流振荡和电压过冲,提高了器件的稳定性和可靠性。(The invention discloses a fast recovery diode in the field of semiconductor power devices. The fast recovery diode comprises an N + type silicon single crystal substrate, an N-type epitaxial layer, a P + type block and a P-type main junction, wherein the number of the P + type blocks is multiple, the N-type epitaxial layer is arranged above the N + type silicon single crystal substrate, the P-type main junction is arranged above the inside of the N-type epitaxial layer, the P + type block is arranged between the N + type silicon single crystal substrate and the N-type epitaxial layer, a front metal layer is arranged above the P-type main junction, and a back metal layer is arranged below the N + type silicon single crystal substrate. The fast recovery diode has extremely short reverse recovery time, fast turn-on and turn-off capability, extremely low current oscillation and voltage overshoot, and improved stability and reliability.)

1. A fast recovery diode, characterized by: the N + type silicon single crystal substrate is arranged on the N + type silicon single crystal substrate, the P + type main junction is arranged above the N-type epitaxial layer, the P + type block is arranged between the N + type silicon single crystal substrate and the N-type epitaxial layer, a front metal layer is arranged above the P-type main junction, and a back metal layer is arranged below the N + type silicon single crystal substrate.

2. A fast recovery diode according to claim 1, wherein: and a silicon dioxide layer is further arranged on the surface of the N-type epitaxial layer, and through holes corresponding to the P-type main junction are formed in the silicon dioxide layer.

3. A fast recovery diode according to claim 1, wherein: the P + type block is cylindrical.

4. A fast recovery diode according to claim 3, wherein: the diameter of the P + type cylinder is 5-20 um, the distance is 5-20 um, the thickness is 0.5-2 um, and the concentration is 1 x 10¹⁶-1×10²⁰cm^-3。

5. A fast recovery diode according to claim 1, wherein: the concentration of the N-type epitaxial layer is 1 x 10¹²-1×10¹⁴cm^-3And the thickness is 30-120 um.

6. A fast recovery diode according to claim 1, wherein: the concentration of the P-type main junction is 1 x 10¹³-1×10¹⁵cm^-3The depth of the junction is 8-12 um.

Technical Field

The invention relates to the technical field of semiconductor power devices, in particular to a fast recovery diode.

Background

The power semiconductor device is used as a core device in a power electronic circuit, can be used for realizing efficient transmission and conversion of electric energy and effective and accurate control in the process of the electric energy, and realizes high-quality and efficient utilization of the electric energy. Due to research and development of power semiconductor devices, power electronic technology has been developed in the direction of large capacity, high frequency, high efficiency, energy saving, high reliability and low cost. Due to the development of high-frequency conversion technology and the requirement of high efficiency and energy conservation, the fast recovery diode is required to have the characteristics of strong high-voltage blocking capability, high switching speed and the like. With the increasing upgrade of circuit structures, circuit designers not only need fast recovery diodes with high frequency performance, but also need diodes with lower oscillation to reduce EMI. At present, chip manufacturers in China can manufacture a fast recovery diode chip with a short reverse recovery time by adopting a P-/N-/N + structure, and can also manufacture a fast recovery diode chip with low oscillation by adopting a P-/N-/N/N + structure, wherein the reverse recovery time of the fast recovery diode chip is extremely short, but the oscillation is serious, the oscillation of the fast recovery diode chip is almost not generated, but the Trr is difficult to be extremely low. Being restricted by high-end production equipment, chip manufacturers in China cannot produce fast recovery diode chips with high frequency and low oscillation performance, so that the fast recovery diode chips mainly depend on imports.

Disclosure of Invention

The invention aims to provide a high-frequency low-oscillation fast-recovery diode structure, which has extremely low reverse recovery time, fast turn-on and turn-off capabilities, extremely low current oscillation and voltage overshoot and improved stability and reliability of devices.

In order to achieve the above purpose, the following technical scheme is adopted by the fast recovery diode of the invention:

a fast recovery diode comprises an N + type silicon single crystal substrate, an N-type epitaxial layer, a P + type block and a P-type main junction, wherein the number of the P + type block is multiple, the N-type epitaxial layer is arranged above the N + type silicon single crystal substrate, the P-type main junction is arranged above the inside of the N-type epitaxial layer, the P + type block is arranged between the N + type silicon single crystal substrate and the N-type epitaxial layer, a front metal layer is arranged above the P-type main junction, and a back metal layer is arranged below the N + type silicon single crystal substrate. The beneficial effect of this step is: based on a P-/N-/N + structure, a P + type block is arranged between N < - > and N < + >, the oscillation of reverse recovery of the fast recovery diode is reduced by adjusting parameters such as the concentration, the volume, the spacing and the like of the P + type block, and the characteristic of extremely short reverse recovery time of the P-/N-/N < + > structure is considered.

Furthermore, a silicon dioxide layer is further arranged on the surface of the N-type epitaxial layer, and through holes corresponding to the P-type main junctions are formed in the silicon dioxide layer.

Further, the P + type block is cylindrical.

Further, the diameter of the P + type cylinder is 5-20 um, the distance is 5-20 um, the thickness is 0.5-2 um, and the concentration is 1 x 10¹⁶-1×10²⁰cm^-3. The base region is introduced with P + to increase the time for the carrier of the base region to be pumped away or compounded, thereby achieving the purposes of reducing the current oscillation and reverse voltage of reverse recovery and realizing low EMI.

Further, the concentration of the N-type epitaxial layer is 1 x 10¹²-1×10¹⁴cm^-3And the thickness is 30-120 um. On the premise of ensuring that the breakdown voltage meets the requirement, the low-doping and low-thickness N-type epitaxial layer is adopted, so that low reverse recovery is realized, and the high-frequency performance of the diode is improved.

Further, the concentration of the P-type main junction is 1X 10¹³-1×10¹⁵cm^-3The depth of the junction is 8-12 um. The lower the set concentration of the P-type main junction, the more favorable the soft recovery characteristic is achieved, the concentration having a significant effect on reducing EMI, and the favorable reverse recovery time.

Compared with the prior art, the invention has the beneficial effects that: the fast recovery diode has extremely short reverse recovery time, fast turn-on and turn-off capability, extremely low current oscillation and voltage overshoot, and improved stability and reliability.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a graph comparing the recovery characteristics of the present invention with conventional products;

the structure comprises a 1N + type silicon single crystal substrate, a 2P + type cylinder, a 3N-type epitaxial layer, a 4P-type main junction, a 5 silicon dioxide layer, a 6 front metal layer and a 7 back metal layer.

Detailed Description

The present invention is further illustrated by the following detailed description, which is to be construed as merely illustrative and not limitative of the remainder of the disclosure, and modifications and variations such as those ordinarily skilled in the art are intended to be included within the scope of the present invention as defined in the appended claims.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "vertical", "peripheral surface" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or orientations or positional relationships that the products of the present invention are conventionally placed when used, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or the element to which the present invention is directed must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Furthermore, the term "vertical" or the like does not imply that the components are required to be absolutely horizontal or overhanging, but rather may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In describing the invention, it is not necessary for a schematic representation of the above terminology to be directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples of the invention and features of different embodiments or examples described herein may be combined and combined by those skilled in the art without contradiction.