CN202601620U - Fast recovery diode - Google Patents

Abstract

The utility model relates to a fast recovery diode which comprises a N type highly doped silicon substrate, a first N type doped semiconductor layer, a second doped semiconductor layer, and a diode anode layer, wherein the first N type doped semiconductor layer is positioned between the second N type doped semiconductor layer and the N type highly doped silicon substrate, the doping concentration of the first N type doped semiconductor layer is lower than that of the second N type doped semiconductor layer, the width of the first N type doped semiconductor layer is 5um-50um, the doping concentration of the first N type doped semiconductor layer is 5e12/cm<3> to 5e14/cm<3>. The fast recovery diode provided by the utility model can provide enough carrier concentration during reverse recovery, thereby being capable of maintaining the softness of current dropping.

Description

Fast recovery diode

Technical field

The utility model relates to a kind of 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, still adopt the novel electric power electric device that self-switching-off capability is arranged, all needs one with it parallel connection and reverse recovery time the diode of weak point; With through the reactive current in the load, suppress simultaneously because of the instantaneous high voltage of oppositely responding to of load current.

In view of the above; The fast recovery diode that many moneys differ from one another is pushed away toward application market; Such as the sonic FRD (Fast Recovery Diodes, fast recovery diode) of IXYS company, the SPT+FRD of ABB AB, the EMCON of Infineon company, HEXFRED of IR company or the like.

Please with reference 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 the effect that electric current is ended rapidly when reverse bias, generally can adopt technology such as reducing hole, anode region 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 on parameter, to obtain comparatively desirable trading off.Such as; The diode of P-i-N structure was able to shorten on reverse recovery time, but oppositely recovered (being that di/dt is too big) 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 yet the practical application circuit.

The utility model content

The purpose of the utility model is to provide a kind of fast recovery diode that can soft recovery.

A kind of fast recovery diode; Comprise a N type highly doped silicon substrate, one the one N type doping semiconductor layer, one the 2nd N type doping semiconductor layer, a diode anode layer; A said 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 a said N type doping semiconductor layer is lower than the doping content of the 2nd N type doping semiconductor layer, and the width of a said N type doping semiconductor layer is that 5um to 50um, doping content are 5e12/cm ³-5e14/cm ³

Further, the doping content N of said the 2nd N type doping semiconductor layer _DAnd the width d of the 2nd 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 charge, V _RBe the reversed bias voltage of operate as normal, E _BVBe critical disruptive field intensity.

Further, the doping content of said the 2nd N type doping semiconductor layer is 3e14/cm ³, the doping content of a said N type doping semiconductor layer is 5e13/cm ³, the width of a said N type doping semiconductor layer is 25um, the width of said the 2nd N type doping semiconductor layer is 35um.

Further, the doping content of a said N type doping semiconductor layer is 5e14/cm ³, the doping content of said the 2nd N type doping semiconductor layer is 1e15/cm ³, the width of a said N type doping semiconductor layer and the 2nd N type doping semiconductor layer is 5um.

Further, the doping content of a said N type doping semiconductor layer is 1e13/cm ³, the doping content of said the 2nd N type doping semiconductor layer is 2e13/cm ³, the width of a said N type doping semiconductor layer and the 2nd N type doping semiconductor layer is 50um.

Above-mentioned fast recovery diode is through changing the doping content of a N type doping semiconductor layer; To form " PNN-N+ " structure; Wherein the doping content of a N type doping semiconductor layer is lower than the doping content of the 2nd N type doping semiconductor layer, so form a NN-knot.When said fast recovery diode is anti-inclined to one side; Because the existence of NN-junction barrier with the reverse extraction that hinders electronics, thereby improves this regional carrier concentration; Make fast recovery diode when reverse the recovery, enough carrier concentrations can be provided, to keep the softness that electric current descends.

Description of drawings

Fig. 1 is the sketch map of existing fast recovery diode.

Fig. 2 is the sketch map of the preferred embodiments of the utility model fast recovery diode.

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

Embodiment

Please refer to Fig. 2; The preferred embodiments of the utility model fast recovery diode comprises a N type highly doped silicon substrate 111, one the one N type doping semiconductor layer 112, one the 2nd N type doping semiconductor layer 123, a diode anode layer 134, and a said 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 a wherein said N type doping semiconductor layer 112 is that 5um to 50um, doping content are 5e12/cm ³-5e14/cm ³The doping content N of said the 2nd N type doping semiconductor layer 123 _DSatisfy formula (1) with the width d of the 2nd 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 charge, V _RBe the reversed bias voltage of operate as normal, EBV is critical disruptive field intensity.

According to the above, the width d of said the 2nd 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 through changing the doping content of a N type doping semiconductor layer 112, to form " PNN-N+ " structure.Wherein the doping content of a N type doping semiconductor layer 112 is lower than the doping content of the 2nd N type doping semiconductor layer 123, so form a NN-knot.When said fast recovery diode is anti-inclined to one side; Because the existence of NN--junction barrier with the reverse extraction that hinders electronics, thereby improves this regional carrier concentration; Make fast recovery diode when reverse the recovery, enough carrier concentrations can be provided, to keep the softness that electric current descends.Can find out from top description; As long as a 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 a said N type doping semiconductor layer 112 doping content that is lower than the 2nd 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 the reverse recovery current oscillogram and the reverse recovery voltage oscillogram of three kinds of fast recovery diodes, and wherein curve A 1 expression the 2nd N type doping semiconductor layer doping content is 3e14/cm ³, a N type doping semiconductor layer doping content is 5e14/cm ³The reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve B 1 expression the 2nd N type doping semiconductor layer doping content is 3e14/cm ³, a N type doping semiconductor layer doping content is 3e14/cm ³The reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve C 1 expression the 2nd N type doping semiconductor layer doping content is 3e14/cm ³, a N type doping semiconductor layer doping content is 5e13/cm ³The reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode.The width of the 2nd N type doping semiconductor layer of above-mentioned three fast recovery diodes is 35um, and the width of a N type doping semiconductor layer is 25um.Can find out that 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 first kind and second kind of fast recovery diode.

Please continue with reference to figure 5 and Fig. 6, it shows the 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 2nd N type doping semiconductor layer doping content is 1e15/cm ³, a N type doping semiconductor layer doping content is 2e15/cm ³The reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve B 2 expressions the 2nd N type doping semiconductor layer doping content is 1e15/cm ³, a N type doping semiconductor layer doping content is 1e15/cm ³The reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve C 2 expressions the 2nd N type doping semiconductor layer doping content is 1e15/cm ³, a N type doping semiconductor layer doping content is 5e14/cm ³The reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode.The 2nd N type doping semiconductor layer of above-mentioned three kinds of fast recovery diodes and the width of a N type doping semiconductor layer are 5um.Can find out that 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 first kind and second kind of fast recovery diode.

Curve A 3 expressions the 2nd N type doping semiconductor layer doping content is 2e13/cm among Fig. 7 and Fig. 8 ³, a N type doping semiconductor layer doping content is 5e13/cm ³The reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve B 3 expressions the 2nd N type doping semiconductor layer doping content is 2e13/cm ³, a N type doping semiconductor layer doping content is 2e13/cm ³The reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode, curve C 3 expressions the 2nd N type doping semiconductor layer doping content is 2e13/cm ³, a N type doping semiconductor layer doping content is 1e13/cm ³The reverse recovery current oscillogram and the reverse recovery voltage oscillogram of fast recovery diode.The 2nd N type doping semiconductor layer of above-mentioned three fast recovery diodes and the width of a N type doping semiconductor layer are 50um.Can find out that 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 first kind and second kind of fast recovery diode.

Can find out from top description; The doping content of the 2nd 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 2nd N type doping semiconductor layer.

The above is merely the preferred embodiment of the utility model; Not in order to restriction the utility model; Any modification of being done within all spirit and principles at the utility model, be equal to replacement and improvement etc., all should be included within the protection range of the utility model.

Claims (5)

1. fast recovery diode; Comprise a N type highly doped silicon substrate, one the one N type doping semiconductor layer, one the 2nd N type doping semiconductor layer, a diode anode layer; A said 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 a said N type doping semiconductor layer is lower than the doping content of the 2nd N type doping semiconductor layer, and the width of a said N type doping semiconductor layer is that 5um to 50um, doping content are 5e12/cm ³-5e14/cm ³

2. fast recovery diode as claimed in claim 1 is characterized in that: the doping content N of said the 2nd N type doping semiconductor layer _DAnd the width d of the 2nd 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 charge, V _RBe the reversed bias voltage of operate as normal, E _BVBe critical disruptive field intensity.

3. fast recovery diode as claimed in claim 1 is characterized in that: the doping content of said the 2nd N type doping semiconductor layer is 3e14/cm ³, the doping content of a said N type doping semiconductor layer is 5e13/cm ³, the width of a said N type doping semiconductor layer is 25um, the width of said the 2nd N type doping semiconductor layer is 35um.

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

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

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