CN201845784U

CN201845784U - High-power high-current density rectifier diode chip

Info

Publication number: CN201845784U
Application number: CN2010202061986U
Authority: CN
Inventors: 金小玲
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-05-28
Filing date: 2010-05-28
Publication date: 2011-05-25
Anticipated expiration: 2020-05-28

Abstract

The utility model relates to a high-power high-current density rectifier diode chip, which belongs to the technical field of manufacture of semiconductor devices and comprises a boron layer, an N-shaped layer and a strong phosphorus layer that are sequentially arranged, wherein the thickness of the boron layer is 50-60 mum, the thickness of the strong phosphorus layer is 10-12 mum, and the thickness of the chip is 180-200 mum. The high-power high-current density rectifier diode chip provided by the utility model adopts the process that phosphorus is diffused and then boron is diffused, a phosphorus (N+) layer is pre-deposited on the surface of a silicon slice, then the N+ layer on one surface is rubbed out, a P+ layer is then diffused, simultaneously, the front edge of the N+ layer is propelled to form a buffer area with gentle concentration distribution, so that the expansion of the space charge area is blocked, the thickness of an N layer is reduced, the tube voltage drop is reduced, in addition, the thickness of the silicon slice can be greatly reduced, and the current density can be greatly increased up to 500A/cm<2>.

Description

A kind of high-power high-current density rectifier diode chip

Technical field

The utility model relates to a kind of high-power high-current density rectifier diode chip, belongs to the semiconductor device processing technology field.

Background technology

The manufacture difficulty of high-power high-current density rectifier diode chip is very big, mainly is because require it to have very large current density, reaches 400A/cm ²More than, and the current density of common rectifier diode is generally 80～100A/cm ², maximum is no more than 200A/cm ²In the prior art, the manufacture process of rectifier diode chip generally adopts and expands the technology that expands phosphorus behind the boron earlier, promptly at first expands boron on two surfaces of N type silicon chip, forms P ⁺The district, then that one of them is surperficial P ⁺The district grinds off, and is grinding off P at last ⁺Phosphorus is expanded on the surface in district, forms N ⁺The district.Because the degree of depth that expands the boron layer is generally at 100-200 μ m, therefore the original silicon chip thickness of selecting must be thicker, this just makes the tube voltage drop of the rectifier diode that is processed at last bigger, makes by the current density of rectifier diode chip just lessly, generally has only 80～100A/cm ²Because its tube voltage drop is big, current density is little, can only adopt bigger silicon area to guarantee to use electric current, this just makes the raw material amount of employing increase, and the ceramic shell overall volume of rectifier diode finished product also increases, cause in the use occupation space bigger, do not meet the principle of energy-saving and emission-reduction low-carbon (LC).

Summary of the invention

The purpose of this utility model is to propose a kind of high-power high-current density rectifier diode chip, changes the structure of existing rectifier diode chip, to improve the current density of rectifier diode, reduces chip volume, saves product cost.

The high-power high-current density rectifier diode chip that the utility model proposes, form by boron layer, N type layer and dense phosphorus layer, described boron layer, N type layer and dense phosphorus layer are arranged in order, the thickness of wherein said boron layer is 50-60 μ m, the thickness of described dense phosphorus layer is 10-12 μ m, and chip thickness is 180-200 μ m.

The high-power high-current density rectifier diode chip that the utility model proposes adopts and expands the technology that expands boron behind the phosphorus earlier, at the pre-deposition last layer phosphorus (N of silicon chip surface elder generation ⁺) layer (about 10-12 μ m), grind off one side N then ⁺Layer (about 10-12 μ m) spreads P again ⁺Layer (about 50-60 μ m) is simultaneously N ⁺Layer forward position advances and forms the buffering area that CONCENTRATION DISTRIBUTION is mild, stops the expansion of space charge region, and attenuate N layer thickness plays the effect that reduces tube voltage drop, and significantly reduced silicon wafer thickness, to have improved current density greatly (up to 500A/cm ²).

Description of drawings

Fig. 1 is the structural representation of the high-power high-current density rectifier diode chip that the utility model proposes.

Fig. 2 is the impurities concentration distribution figure that utilizes the rectifier diode chip of the inventive method preparation, and among Fig. 2, the left side ordinate is a boron layer concentration, and the right side ordinate is a phosphorus layer concentration, and abscissa is that junction depth and sheet are thick.

Among Fig. 1, the 1st, boron layer, the 2nd, N type layer, the 3rd, dense phosphorus layer.

Embodiment

The high-power high-current density rectifier diode chip that the utility model proposes, its structure are made up of boron layer 1, N type layer 2 and dense phosphorus layer 3 as shown in Figure 1.Boron layer 1, N type layer 2 and dense phosphorus layer 3 are arranged in order, and wherein the thickness of boron layer is 50-60 μ m, and the thickness of dense phosphorus layer is 10-12 μ m, and the chip gross thickness is 180-200 μ m.

The high-power high-current density rectifier diode chip that the utility model proposes, can adopt the following steps preparation:

(1) adopt two the diffusion into the surface phosphorus of latex phosphorus source method of diffusion at N type silicon chip, making each dense phosphorus layer thickness of formation is 10-12 μ m, and diffusion process is:

(1-1) add phosphorus pentoxide in the silicon dioxide latex, the mass ratio of adding is: the silicon dioxide latex: phosphorus pentoxide=1: 0.1-0.5, make dissolving fully, and become phosphorus containing silicon dioxide latex source;

(1-2) above-mentioned phosphorus containing silicon dioxide latex source is coated on two surfaces of N type silicon chip, coating layer thickness is the 3000-4000 dust;

(1-3) the N type silicon chip behind the gluing is placed 100 ℃-200 ℃ toasted 5-10 minute down;

(1-4) the N type silicon chip after the above-mentioned baking is sent in the diffusion furnace, spread 1.5-2.5 hour down, become dense phosphorus layer at the silicon chip dihedron at 1200 ℃-1260 ℃.

(2) one in above-mentioned two dense phosphorus layers is ground off, grinding off the diffusion into the surface boron of dense phosphorus layer, the thickness that makes the boron layer is 50-60 μ m, and diffusion process is:

(2-1) add diboron trioxide in the silicon dioxide latex, the mass ratio of adding is: the silicon dioxide latex: diboron trioxide=1000: 20-30, make dissolving fully, and become boracic silicon dioxide latex source;

(2-2) above-mentioned boracic silicon dioxide dissolving source is coated on the surface that has ground off dense phosphorus layer of N type silicon chip, coating layer thickness is the 6000-8000 dust;

(2-3) the N type silicon chip behind the gluing is placed 100 ℃-200 ℃ toasted 5-10 minute down;

(2-4) the N type silicon chip after the above-mentioned baking is sent in the diffusion furnace, spread 12-18 hour down at 1200 ℃-1260 ℃.

With the thickness by method for preparing is that 200 rectifier diode chip is an example, if with the existing manufacture method that expands phosphorus behind the boron that expands earlier, reach same high current density, the diameter of its rectifier diode chip must reach 70mm, and effective area reaches 35cm ², and the rectifier diode chip with the utility model structure, its diameter needs only 46mm, and effective area is about 15cm ², the on-state average current that allows to pass through is 7000A, current density can reach 467A/cm ², pressure drop of on-state crest value is a kind of high density and high current rectifier diode less than 1.2V.This shows that the diode chip for backlight unit that the utility model proposes has been saved raw material, and reduced by the in use shared space of the diode of this chip manufacturing.

Claims

1. high-power high-current density rectifier diode chip, it is characterized in that this rectifier diode chip is made up of boron layer, N type layer and phosphorus layer, described boron layer, N type layer and phosphorus layer are arranged in order, the thickness of wherein said boron layer is 50-60 μ m, the thickness of described phosphorus layer is 10-12 μ m, and chip thickness is 180-200 μ m.