CN200976352Y - Power type separating device metallic oxide semiconductor field effect transistor - Google Patents

Abstract

The utility model discloses a power separating device MOSFET (Metal Oxide Semiconductor Field Effect Transistor), which comprises an isolation layer, a boundary region composed by a composite semiconductor material layer and an oxidation diffusion layer, an avalanche resistance unit with a barrier layer; wherein the left end of the first section of the composite semiconductor material layer does not even up with the left end of the oxidation diffusion layer, and also an isolation coating is arranged at the common end of the neighboring regions of the composite semiconductor material layer and the oxidation diffusion layer which is provided with a bottom isolation layer on the horizontal surface of the oxidation diffusion layer; contact windows are arranged between the isolation coating and the bottom isolation layer as well as between the isolation coating and the isolation layer with metal materials to form an intensified boundary region structure; the contact window is connected with the source terminal. The barrier layer of the avalanche energy-tolerance unit takes generally the shape of a rectangle, the long side of which is horizontally arranged between the N+ channels, and the length of the side with longer barrier layer is greater than the width of the N+ channels. The utility model has the advantages of boosting the breakdown voltage and enhancing the energy-tolerance capacity.

Description

Power type segregator metal oxide semiconductor fieldistor

Technical field

The utility model relates to semiconductor technology, specifically a kind of power type segregator metal oxide semiconductor fieldistor (MOSFET).

Background technology

In the prior art, the borderline region structure of power-type discrete device MOSFET (referring to Fig. 1-1), be generally: establish composite semiconductor material layer 2 (POLY) between separator 1-1 (adopting boron-phosphorosilicate glass (BPSG)) and the oxide-diffused layer 3 (FOX), composite semiconductor material layer 2 is divided into two sections, first section composite semiconductor material layer left end and oxide-diffused layer left end are evened up, and the right-hand member of second section composite semiconductor material layer right-hand member and separator 1-1 and oxide-diffused layer 3 is evened up; Oxide-diffused layer 3 left end and region of activation 4 are adjacent; Weak point is: existing structure does not have great variation to the lifting of breakdown voltage, even change epitaxial wafer (EPI) material, can only reach 60V yet.In addition, the structure of MOSFET device runs into special occasions sometimes on using, and for example also must flow through specific currents contrary the connecing under the situation of high voltage, and Avalanche this moment (the anti-energy of snowslide) just needs to consider.The MOSFET passage is a vertical-type, so the many barrier layers (Heavy Body) of the width between two contiguous N+ passages.The barrier layer width can influence the ability of the anti-energy of snowslide, and the wide more then ability of width is strong more.One side width of barrier layer has only 2.5um in the anti-energy of the snowslide at present cellular construction, and identical with the N+ channel width, integral body is square, and snowslide is anti-ability to be 300mw.With reference to figure 2-1 and Fig. 2-1-1, deficiency is to reckon without the ability of the required anti-energy of snowslide of practical application, simply pursue small size, low-cost and cause in the application and burn easily.The anti-energy of the snowslide ability of the borderline region breakdown voltage of power-type discrete device MOSFET lifting effect and the anti-energy of snowslide unit is not ideal enough at present in a word.

The utility model content

The purpose of this utility model is to provide a kind of can promote breakdown voltage, improve the anti-power-type discrete device MOSFET that can ability of snowslide simultaneously.

The scheme that its technical problem that solves the utility model adopts is to comprise: borderline region of being made up of separator, composite semiconductor material layer and oxide-diffused layer and the snowslide that has barrier layer are anti-can the unit, establish the composite semiconductor material layer between its separator and the oxide-diffused layer, the composite semiconductor material layer is divided into two sections, and the right-hand member of second section composite semiconductor material layer right-hand member and separator and oxide-diffused layer is evened up; Oxide-diffused layer left end and region of activation are adjacent; Wherein: first section composite semiconductor material layer left end structure do not evened up with oxide-diffused layer left end, and adds coated separator at the common end of composite semiconductor material layer and oxide-diffused layer adjacent domain; Also on oxide-diffused layer horizontal plane, add end separator; Between coated separator and end separator, and offer contact window by metal material between coated separator and the separator, constitute enhanced type borderline region structure; Described contact window is connected with source electrode;

The region of activation adjacent with oxide-diffused layer one end described in the utility model is positioned at the below of end separator, contact window and coated separator; First section composite semiconductor material layer left end is shorter than oxide-diffused layer left end; Described contact window is positioned on the path of electron stream, with the same material of source electrode.

In addition, barrier layer integral body is rectangle in the anti-energy of the described snowslide cellular construction, and its long limit level is to being arranged between the N+ passage, and the length on one side that barrier layer is long is greater than the N+ channel width.

The beneficial effects of the utility model are:

1. improved the anti-energy of snowslide ability.The utility model has strengthened the width of the barrier layer between two N+, and the zone of volume concentration range P+ is strengthened, thereby has reduced the resistance of semiconductor and metal level, reaches the purpose that increases the anti-energy of snowslide intensity.

2. lifting breakdown voltage.Because the utility model improves borderline region, adds end separator, coated separator, and offers contact window, constitutes a kind of enhanced type borderline region, it can raise breakdown voltage and reach 200V.

3. cost is low.Improved, the enhanced type border is identical with the manufacturing materials of device own, need not change extra material, thereby saved cost of manufacture effectively.

Description of drawings

Fig. 1-1 is MOSFET borderline region (termination) part-structure schematic diagram in the prior art.

Fig. 1-2 is that the utility model borderline region (termination) part-structure improves figure.

Fig. 2-1 is the anti-energy of MOSFET snowslide (avalanche) cellular construction schematic diagram in the prior art.

Fig. 2-1-1 is the vertical view of Fig. 2-1.

Fig. 2-2 is that the anti-energy of the utility model snowslide (avalanche) cellular construction improves figure.

Fig. 2-2-1 is the vertical view of Fig. 2-2.

Embodiment

The utility model is described in further detail below in conjunction with drawings and Examples.

Embodiment 1

In the prior art, to the borderline region of MOSFET device this partly design can be in different ways, some uses different materials, some uses different structure, the utility model has been done further improvement (referring to Fig. 1-2), promptly be: be located on the basis that composite semiconductor material layer 2 between separator 1-1 and the oxide-diffused layer 3 is divided into two sections, first section composite semiconductor material layer 2 left end structure do not evened up with oxide-diffused layer 3 left end and (is shorter than oxide-diffused layer 3 left end, if first section composite semiconductor material layer 2 left end is longer than oxide-diffused layer 3 left end, can cause electric leakage); And the common end in composite semiconductor material layer 2 and oxide-diffused layer 3 adjacent domain adds coated separator 1-2; Further, also on oxide-diffused layer 3 horizontal plane, add end separator 1-3, between coated separator 1-2 and end separator 1-3, and offer contact window 5 (passing through metal material) between coated separator 1-2 and the separator 1-1, described contact window 5 is positioned on the path of electron stream, is connected with source electrode and same material; More than constitute the enhanced type borderline region; In addition, the region of activation 4 adjacent with oxide-diffused layer 3 one end is positioned at the below of end separator 1-3, contact window 5 and coated separator 1-2 simultaneously; The advantage of this design has:

1) electron transfer rate is accelerated.Because the utility model is on the composite semiconductor material layer basis that adds above the zone, region of activation, add end separator 1-3, coated separator, between coated separator 1-2 and end separator 1-3, and offer contact window 5 between coated separator 1-2 and the separator 1-1, electron transfer rate is accelerated, made its electronic energy fast transferring to grid.

2) can promote breakdown voltage.The enhanced type borderline region of improvement structure of the present utility model can raise breakdown voltage and reach 200V.Only need to change epitaxial wafer, and need can not be suitable for interior at 200V in redesign.

Device described in the utility model is high-power type MOSFET, and its size of components is bigger, and the composite semiconductor material layer that can arrive grid rapidly and added for the electronics speed that can make the assembly periphery can overcome the slower problem of power device mobility (Mobility).Please refer to following principle:

Electron mobility μ m=q τ c/mn ^*

Electrokinetic migration rate μ p=q τ c/mp ^*

Wherein: q represents the electron charge number, and average time, mn are collided in τ c representative ^*Represent electron effective mass, mp ^*Represent electronic effective mass.

3) cost is low.The material that is adopted in the preparation of the present utility model is identical with the manufacturing materials of device own, need not change extra new material, so cost is lower.

Embodiment 2

The improvement of the anti-energy of the utility model snowslide cellular construction is shown in Fig. 2-2,2-2-1, wherein barrier layer integral body is rectangle, the length on long one side is greater than the N+ channel width, in other words, under the constant situation of vertical edges width, its long limit level of horizontal sides width lengthening (as: be enlarged to 3.5um, and foursquare four limits being 2.5um in the prior art) is to being arranged between the N+ passage; In order to reduce the intensity of resistance, the anti-energy of increase snowslide.

Among Fig. 2-2: 2 is composite semiconductor material layer (POLY); 22 is grid oxic horizon; 23 is the N+ passage; 24 is barrier layer (Heavy Body); 25 is basic P layer (Body); 26 is epitaxial wafer (EPI); 27 is substrate (N+substrae).

Strengthened in width between two N+ zone of then representing volume concentration P+ that broadens as can be known by Fig. 2-2, then resistance can reduce, and can allow the electric current of process then to increase.

A low-resistance interface can provide the conducting of doing both direction between metal and the semiconductor.Because the electric group of ratio that can be defined as voltage and electric current, Yin Wendu and the electric current increase means that the electricity group reduces.Electric current is proportional to the net velocity of carrier number and direction of an electric field.

Below be the resistance calculations mode of MOSFET, sharpen understanding with helping:

R _ON＝R _N ⁺+R _cH+R _A+R _J+R _E+R _s

Wherein: R _N ⁺Be N ⁺The resistance that diffuse source (source diffusion) is produced;

R _CHThe resistance that is produced for passage (channel);

R _AThe resistance that is produced for Guinier-Preston zone (accumulation layer);

R _JThe resistance that is produced for the drift region (drift region) between N type substrate (N base);

R _EThe resistance that is produced for epitaxial wafer (EPI region);

R _SThe resistance that is produced for substrate (substrate).

Desirable $R_{\mathrm{ON},\mathrm{sp}}=\frac{W_D}{q{\mathrm{\μ}}_n{N}_D}=5.93\×{10}^{-9}{\left(\mathrm{BVdss}\right)}^{2.5};$

Wherein:: W _DPeak width, N _D: EPI directly goes into chemical element concentration, q: electronics, μ _n: electron mobility, BVdss: breakdown voltage.

As seen, the width that increases the P+ zone can reduce the resistance of semiconductor and metal level, reaches the intensity that increases the anti-energy of snowslide.

Claims (5)

1. power type segregator metal oxide semiconductor fieldistor, comprise borderline region of forming by separator (1-1), composite semiconductor material layer (2) and oxide-diffused layer (3) and the snowslide that has barrier layer anti-energy unit, establish composite semiconductor material layer (2) between its separator (1-1) and the oxide-diffused layer (3), composite semiconductor material layer (2) is divided into two sections, and the right-hand member of second section composite semiconductor material layer right-hand member and separator (1-1) and oxide-diffused layer (3) is evened up; Oxide-diffused layer (3) left end and region of activation (4) are adjacent; It is characterized in that: first section composite semiconductor material layer (2) left end structure is not evened up with oxide-diffused layer (3) left end, and adds coated separator (1-2) at the common end of composite semiconductor material layer (2) and oxide-diffused layer (3) adjacent domain; Also on oxide-diffused layer (3) horizontal plane, add end separator (1-3); Between coated separator (1-2) and end separator (1-3), and offer contact window (5) by metal material between coated separator (1-2) and the separator (1-1), constitute enhanced type borderline region structure; Described contact window (5) is connected with source electrode.

2. according to the described power type segregator metal oxide semiconductor fieldistor of claim 1, it is characterized in that: barrier layer integral body is rectangle in the anti-energy of the described snowslide cellular construction, its long limit level is to being arranged between the N+ passage, and the length on one side that barrier layer is long is greater than the N+ channel width.

3. according to the described power type segregator metal oxide semiconductor fieldistor of claim 1, it is characterized in that: the region of activation (4) adjacent with oxide-diffused layer (3) one end is positioned at the below of end separator (1-3), contact window (5) and coated separator (1-2).

4. according to the described power type segregator metal oxide semiconductor fieldistor of claim 1, it is characterized in that: first section composite semiconductor material layer (2) left end is shorter than oxide-diffused layer (3) left end.

5. according to the described power type segregator metal oxide semiconductor fieldistor of claim 1, it is characterized in that: described contact window (5) is positioned on the path of electron stream, with the same material of source electrode.

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