CN103311278A - Fast recovery diode and method for manufacturing fast recovery diode - Google Patents

Abstract

The invention provides a fast recovery diode, which comprises an N type high-doping silicon substrate, a first N type doping semiconductor layer, a second N type doping semiconductor layer and a diode anode layer, wherein the first N type doping semiconductor layer is positioned between the second N type doping semiconductor layer and the N type high-doping silicon substrate, and the doping concentration of the first N type doping semiconductor layer is lower than the doping concentration of the second N type doping semiconductor layer. The fast recovery diode can provide the sufficient current carrier concentration during the reverse recovery, so the current fall softness can be maintained. The invention also provides a method for manufacturing the fast recovery diode.

Description

Fast recovery diode and the method for making this diode

Technical field

The method that the present invention relates to a kind of diode and make this diode.

Background technology

Development along with power electronic technology, the application of various frequency changer circuits, chopper circuit constantly enlarges, no matter the major loop in these Power Electronic Circuit is the thyristor that adopts commutation cutoff, or adopt the novel power transistor that self-switching-off capability is arranged, all need a with it diode in parallel and that reverse recovery time is shorter, with by the reactive current in the load, suppress simultaneously because of the instantaneous high voltage of oppositely responding to of load current.

Accordingly, the fast recovery diode that many moneys differ from one another is pushed away toward application market, sonic FRD (Fast Recovery Diodes, fast recovery diode), the SPT+FRD of ABB AB, the EMCON of Infineon company, HEXFRED of IR company etc. such as IXYS company.

Please refer to Fig. 1, it shows a kind of fast recovery diode of P-i-N structure, and it comprises diode anode district 101, diode tagma 102 and diode cathode district 103.Be to reach to make the rapidly effect of cut-off of electric current when reverse bias, generally can adopt technology such as reducing anode region hole injection efficiency and overall minority carrier life time control, with the CONCENTRATION DISTRIBUTION of the charge carrier that changes diode tagma 102.But these technology often are difficult to make fast recovery diode to obtain comparatively desirable trading off in parameter.Such as, the diode of P-i-N structure was shortened in reverse recovery time, but oppositely recovered (being that di/dt is too large) really up to the mark, thereby can cause too high reverse recovery voltage, do not burn even fast recovery diode itself punctures, can produce harmful effect to the practical application circuit yet.

Summary of the invention

The object of the present invention is to provide a kind of can soft recovery fast recovery diode and the manufacture method of this diode.

A kind of fast recovery diode, comprise a N-type highly doped silicon substrate, one first N-type doping semiconductor layer, one second N-type doping semiconductor layer, a diode anode layer, described the first N-type doping semiconductor layer is between the second N-type doping semiconductor layer and N-type highly doped silicon substrate, and the doping content of described the first N-type doping semiconductor layer is lower than the doping content of the second N-type doping semiconductor layer.

A kind of manufacture method of fast recovery diode comprises:

Make low-doped extension at a N-type highly doped silicon substrate, to form one first N-type doping semiconductor layer;

Make a place at described the first N-type doping semiconductor layer and prolong, to form one second N-type doping semiconductor layer, the doping content of wherein said the first N-type doping semiconductor layer is lower than the doping content of the second N-type doping semiconductor layer; And

Inject p type impurity at described the second N-type doping semiconductor layer and diffuse to form again the diode anode layer.

Above-mentioned fast recovery diode and preparation method thereof is by changing the doping content of the first N-type doping semiconductor layer, to form " PNN-N+ " structure, wherein the doping content of the first N-type doping semiconductor layer is lower than the doping content of the second N-type doping semiconductor layer, so form a NN-knot.When described fast recovery diode is anti-inclined to one side, because the existence of NN-junction barrier will hinder the reverse extraction of electronics, thereby improves this regional carrier concentration, make fast recovery diode when oppositely recovering, can provide enough carrier concentrations, the softness that descends to keep electric current.

Description of drawings

Fig. 1 is the schematic diagram of existing fast recovery diode.

Fig. 2 is the schematic diagram of the better embodiment of fast recovery diode of the present invention.

Fig. 3-8 is the reverse recovery current oscillogram of fast recovery diode of the present invention and reverse recovery voltage oscillogram.

Fig. 9 is the flow chart of better embodiment of the manufacture method of fast recovery diode of the present invention.

Embodiment

Please refer to Fig. 2, the better embodiment of fast recovery diode of the present invention comprises a N-type highly doped silicon substrate 111, one first N-type doping semiconductor layer 112, one second N-type doping semiconductor layer 123, a diode anode layer 134, and described the first N-type doping semiconductor layer 112 is between the second N-type doping semiconductor layer 123 and N-type highly doped silicon substrate 111.The width of wherein said the first N-type doping semiconductor layer 112 is that 5um to 50um, doping content are 5e12/cm ³-5e14/cm ³The doping content N of described the second N-type doping semiconductor layer 123 _DSatisfy formula (1) with the width d of the second N-type doping semiconductor layer 123:

ε in the formula (1) wherein _rBe the dielectric constant of silicon, ε ₀Be permittivity of vacuum, e refers to Single Electron electric weight, V _RBe the reversed bias voltage of normal operation, EBV is critical breakdown strength.

According to the above, the width d of described the second N-type doping semiconductor layer 123 then satisfies formula (2):

${\left(\frac{2{\mathrm{\&epsiv;}}_r{\mathrm{\&epsiv;}}_0}{e}\frac{V_R}{N_D}\right)}^{\frac{1}{2}}<d<\frac{{\mathrm{\&epsiv;}}_r{\mathrm{\&epsiv;}}_0{E}_{\mathrm{BV}}}{{\mathrm{eN}}_D}---\left(2\right).$

Above-mentioned fast recovery diode is by changing the doping content of the first N-type doping semiconductor layer 112, to form " PNN-N+ " structure.Wherein the doping content of the first N-type doping semiconductor layer 112 is lower than the doping content of the second N-type doping semiconductor layer 123, so form a NN-knot.When described fast recovery diode is anti-inclined to one side, because the existence of NN-junction barrier will hinder the reverse extraction of electronics, thereby improves this regional carrier concentration, make fast recovery diode when oppositely recovering, can provide enough carrier concentrations, the softness that descends to keep electric current.Can find out from top description, as long as the first N-type doping semiconductor layer 112 is between the second N-type doping semiconductor layer 123 and N-type highly doped silicon substrate 111, and the doping content of described the first N-type doping semiconductor layer 112 doping content that is lower than the second N-type doping semiconductor layer 123 can realize keeping the purpose of the softness that electric current descends.

Please continue with reference to figure 3 and Fig. 4, it shows reverse recovery current oscillogram and the reverse recovery voltage oscillogram of three kinds of fast recovery diodes, and wherein curve A 1 expression the second N-type doping semiconductor layer doping content is 3e14/cm ³, the first N-type doping semiconductor layer doping content is 5e14/cm ³Reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve B 1 expression the second N-type doping semiconductor layer doping content is 3e14/cm ³, the first N-type doping semiconductor layer doping content is 3e14/cm ³Reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve C 1 expression the second N-type doping semiconductor layer doping content is 3e14/cm ³, the first N-type doping semiconductor layer doping content is 5e13/cm ³Reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode.The width of the second N-type doping semiconductor layer of above-mentioned three fast recovery diodes is 35um, and the width of the first N-type doping semiconductor layer is 25um.Can find out from Fig. 3 and Fig. 4, the reverse recovery current softness of above-mentioned the third fast recovery diode and reverse recovery voltage have obtained improvement to a certain degree with respect to the first and the second fast recovery diode.

Please continue with reference to figure 5 and Fig. 6, it shows reverse recovery current oscillogram and the reverse recovery voltage oscillogram of other three kinds of fast recovery diodes, and wherein curve A 2 expressions the second N-type doping semiconductor layer doping content is 1e15/cm ³, the first N-type doping semiconductor layer doping content is 2e15/cm ³Reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve B 2 expressions the second N-type doping semiconductor layer doping content is 1e15/cm ³, the first N-type doping semiconductor layer doping content is 1e15/cm ³Reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve C 2 expressions the second N-type doping semiconductor layer doping content is 1e15/cm ³, the first N-type doping semiconductor layer doping content is 5e14/cm ³Reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode.The second N-type doping semiconductor layer of above-mentioned three kinds of fast recovery diodes and the width of the first N-type doping semiconductor layer are 5um.Can find out from Fig. 5 and Fig. 6, the reverse recovery current softness of above-mentioned the third fast recovery diode and reverse recovery voltage have obtained improvement to a certain degree with respect to the first and the second fast recovery diode.

Curve A 3 expressions the second N-type doping semiconductor layer doping content is 2e13/cm among Fig. 7 and Fig. 8 ³, the first N-type doping semiconductor layer doping content is 5e13/cm ³Reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve B 3 expressions the second N-type doping semiconductor layer doping content is 2e13/cm ³, the first N-type doping semiconductor layer doping content is 2e13/cm ³Reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve C 3 expressions the second N-type doping semiconductor layer doping content is 2e13/cm ³, the first N-type doping semiconductor layer doping content is 1e13/cm ³Reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode.The second N-type doping semiconductor layer of above-mentioned three fast recovery diodes and the width of the first N-type doping semiconductor layer are 50um.Can find out from Fig. 7 and Fig. 8, the reverse recovery current softness of above-mentioned the third fast recovery diode and reverse recovery voltage have obtained improvement to a certain degree with respect to the first and the second fast recovery diode.

Can find out from top description, the doping content of the second N-type doping semiconductor layer of above-mentioned fast recovery diode need guarantee that fast recovery diode is under its operating voltage, the width of depletion layer can not make fast recovery diode breakdown under the bias condition less than rated voltage simultaneously less than the width of the second N-type doping semiconductor layer.

Please refer to Fig. 9, the better embodiment of the manufacture method of fast recovery diode of the present invention may further comprise the steps:

Step S51: make low-doped extension at N-type highly doped silicon substrate 111, to form one first N-type doping semiconductor layer 112, the width of wherein said the first N-type doping semiconductor layer 112 is in the 5um-50um scope, and doping content is at 5e12/cm ³-5e14/cm ³In the scope.

Step S52: continue making place at the first N-type doping semiconductor layer 112 and prolong, to form one second N-type doping semiconductor layer 123, the doping content N of wherein said the second N-type doping semiconductor layer 123 _DAnd width d satisfies following formula:

${\left(\frac{2{\mathrm{\&epsiv;}}_r{\mathrm{\&epsiv;}}_0}{e}\frac{V_R}{N_D}\right)}^{\frac{1}{2}}<d<\frac{{\mathrm{\&epsiv;}}_r{\mathrm{\&epsiv;}}_0{E}_{\mathrm{BV}}}{{\mathrm{eN}}_D},$ $\frac{2{\mathrm{\&epsiv;}}_r{\mathrm{\&epsiv;}}_0{\mathrm{<figure-callout\; id="2"\; label="V\; R\; ed"\; filenames="HSA00000683920900031.png,HSA00000683920900041.png"\; state="\{\{state\}\}">V</figure-callout>}}_R}{{\mathrm{ed}}^{}}<N_D<\frac{{\mathrm{\&epsiv;}}_r{\mathrm{\&epsiv;}}_0{E}_{\mathrm{BV}}}{\mathrm{ed}},$ Wherein.

Step S53: inject p type impurity at the second N-type doping semiconductor layer 123 and diffuse to form again diode anode layer 134.

Certainly, after the step S53, still need and to carry out steps such as carrier lifetime control, front metal and back metal.Because it is identical with existing diode, therefore do not repeat them here.

The above only is preferred embodiment of the present invention, not in order to limiting the present invention, all any modifications of doing within the spirit and principles in the present invention, is equal to and replaces and improvement etc., all should be included within protection scope of the present invention.

Claims (12)

1. fast recovery diode, comprise a N-type highly doped silicon substrate, one first N-type doping semiconductor layer, one second N-type doping semiconductor layer, a diode anode layer, described the first N-type doping semiconductor layer is between the second N-type doping semiconductor layer and N-type highly doped silicon substrate, and the doping content of described the first N-type doping semiconductor layer is lower than the doping content of the second N-type doping semiconductor layer.

2. fast recovery diode as claimed in claim 1, it is characterized in that: the width of described the first N-type doping semiconductor layer is that 5um to 50um, doping content are 5e12/cm ³-5e14/cm ³

3. such as each described fast recovery diode among the claim 1-2, it is characterized in that: the doping content of described the first N-type doping semiconductor layer is 5e13/cm ³, the doping content of described the second N-type doping semiconductor layer is 3e14/cm ³, the width of described the first N-type doping semiconductor layer is 25um, the width of described the second N-type doping semiconductor layer is 35um.

4. such as each described fast recovery diode among the claim 1-2, it is characterized in that: the doping content of described the first N-type doping semiconductor layer is 5e14/cm ³, the doping content of described the second N-type doping semiconductor layer is 1e15/cm ³, the width of described the first N-type doping semiconductor layer and the second N-type doping semiconductor layer is 5um.

5. such as each described fast recovery diode among the claim 1-2, it is characterized in that: the doping content of described the first N-type doping semiconductor layer is 1e13/cm ³, the doping content of described the second N-type doping semiconductor layer is 2e13/cm ³, the width of described the first N-type doping semiconductor layer and the second N-type doping semiconductor layer is 50um.

6. fast recovery diode, comprise a N-type highly doped silicon substrate, one first N-type doping semiconductor layer, one second N-type doping semiconductor layer, a diode anode layer, described the first N-type doping semiconductor layer is between the second N-type doping semiconductor layer and N-type highly doped silicon substrate, the doping content of described the first N-type doping semiconductor layer is lower than the doping content of the second N-type doping semiconductor layer, the doping content N of described the second N-type doping semiconductor layer _DAnd the width d of the second N-type doping semiconductor layer satisfies formula

ε wherein _rBe the dielectric constant of silicon, ε ₀Be permittivity of vacuum, e refers to Single Electron electric weight, V _RBe the reversed bias voltage of normal operation, E _BVBe critical breakdown strength.

7. the manufacture method of a fast recovery diode comprises:

Make low-doped extension at a N-type highly doped silicon substrate, to form one first N-type doping semiconductor layer;

Make a place at described the first N-type doping semiconductor layer and prolong, to form one second N-type doping semiconductor layer, the doping content of wherein said the first N-type doping semiconductor layer is lower than the doping content of the second N-type doping semiconductor layer; And

Inject p type impurity at described the second N-type doping semiconductor layer and diffuse to form again the diode anode layer.

8. the manufacture method of fast recovery diode as claimed in claim 7, it is characterized in that: the width of described the first N-type doping semiconductor layer is in the 5um-50um scope, and doping content is at 5e12/cm ³-5e14/cm ³In the scope.

9. the manufacture method of fast recovery diode as claimed in claim 8 is characterized in that: the doping content N of described the second N-type doping semiconductor layer _DAnd width d satisfies following formula:

ε wherein _rBe the dielectric constant of silicon, ε ₀Be permittivity of vacuum, e refers to Single Electron electric weight, V _RBe the reversed bias voltage of normal operation, E _BVBe critical breakdown strength.

10. such as the manufacture method of each described fast recovery diode among the claim 7-10, it is characterized in that: the doping content of described the first N-type doping semiconductor layer is 5e13/cm ³, the doping content of described the second N-type doping semiconductor layer is 3e14/cm ³, the width of described the first N-type doping semiconductor layer is 25um, the width of described the second N-type doping semiconductor layer is 35um.

11. the manufacture method such as each described fast recovery diode among the claim 7-10 is characterized in that: the doping content of described the first N-type doping semiconductor layer is 5e14/cm ³, the doping content of described the second N-type doping semiconductor layer is 1e15/cm ³, the width of described the first N-type doping semiconductor layer and the second N-type doping semiconductor layer is 5um.

12. the manufacture method such as each described fast recovery diode among the claim 7-10 is characterized in that: the doping content of described the first N-type doping semiconductor layer is 1e13/cm ³, the doping content of described the second N-type doping semiconductor layer is 2e13/cm ³, the width of described the first N-type doping semiconductor layer and the second N-type doping semiconductor layer is 50um.

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