A kind of improved mixed-rectification diode structure
Technical field
The utility model relates to a kind of diode, specifically a kind of mixed-rectification diode structure.
Background technology
Carborundum (SiC) is typical case's representative of third generation semi-conducting material; Also be that present crystal technique and device manufacture level are the most ripe, one of most widely used semiconductor material with wide forbidden band, can produce the excellent more high temperature (300~500 ℃) of performance, high frequency, high power, high-speed, radioresistance device.Under same withstand voltage and current condition, the drift zone resistance of SiC device is lower 200 times than silicon, even the conduction voltage drop of high withstand voltage SiC FET, also much lower than mono-polar, ambipolar silicon device; Can reach the 10ns magnitude switching time of SiC device, and have very superior FBSOA; The SiC power device, performance index are than the taller one magnitude of GaAs device.The SiC power device can significantly reduce the energy consumption of electronic equipment, so the SiC power device also is described as " green energy resource " device of drive " new forms of energy revolution ".
PiN diode and Schottky diode are two kinds of the most frequently used power rectifiers.Fig. 2 has provided common junction barrier schottky diode device architecture.The I-V characteristic and the PN junction diode of Schottky diode are very similar, but the electric current composition is different.The Schottky diode of mono-polar has switching speed faster than ambipolar P-i-N diode, yet the reverse leakage current of Schottky diode is big, and breakdown potential is forced down, and is not suitable for high-voltage applications.Have simultaneously SBD fast and the high voltage bearing device of P-i-N be best choice.This diode is called JBS (Junction Barrier Schottky) or MPS (Merged PiN/Schottky).PN junction is integrated in the Schottky junction structure, and the depletion region of PN junction is shielded from schottky interface outside the High-Field when applied in reverse, has avoided Schottky barrier to reduce effect, and reverse leakage current is reduced greatly.MPS has thick drift region, is suitable for high-pressure work.The JBS device adopts the low metal of Schottky barrier, has reduced forward voltage drop, and its reverse leakage current reduces owing to the screen effect of PN junction.Forward conduction characteristics is determined by Schottky contacts, and reverse blocking is determined by PN junction, so the switching speed of this device is very fast.
Summary of the invention
The purpose of the utility model is to provide a kind of and is not sacrificing the device forward characteristic, under the prerequisite of output capacitance, can improve the withstand voltage improved mixed-rectification diode structure of junction barrier schottky diode device.
The purpose of the utility model is achieved in that
Comprise N
+Substrate zone 100, N type drift region 101, active area knot P
+Part 102, first's anode electrode 104, cathode electrode 105, silicon dioxide layer 106, second portion anode electrode 107; Also include source region knot P part 103, said active area knot P part 103 is surrounded by source region knot P
+Part 102.
The utility model can also comprise:
1, the doping content of active area knot P part 103 is lower than active area knot P
+The doping content of part 102.
2, the metal of first's anode electrode 104 and cathode electrode 105 contacts with N type drift region 101 and is ohmic contact, second portion anode electrode 107 and active area knot P
+Part 102 contacts Schottky contacts with active area knot P part 103, and first's anode electrode 104 and second portion anode electrode 107 short circuits.
A kind of improved mixed-rectification diode structure of the utility model can be through the doping content and the two-dimensional of optimal design N type drift region 101, and field oxide is the two-dimensional of silicon dioxide layer 106.The utility model structure not only PN junction place has the peak electric field point, and at active area knot P
+Also there is the peak electric field point in the edge in part 102 zones; This makes that PN junction knee peak electric field point is lower than common junction barrier schottky diode at identical negative sense bias voltage, this shows that a kind of improved mixed-rectification diode structure of the utility model has the withstand voltage characteristics that promote significantly.
The utility model provides a kind of improved mixed-rectification diode structure.Junction termination technique ring and diode active area are formed simultaneously, and all active area knot P
+Part 102 all forms in active area knot P part 103 zones, is not sacrificing the device forward characteristic, under the prerequisite of output capacitance, has improved the withstand voltage of junction barrier schottky diode device.The utility model and common MPS, JBS process compatible have very strong exploitativeness, more are prone to satisfy the application requirements of power electronic system.
The structural parameters of MPS, JBS device mainly are schottky barrier height, injection window, Schottky contacts proportion, epitaxial layer concentration, epitaxy layer thickness etc.The puncture voltage of MPS, JBS depends on semiconductor breakdown electric field, outer layer doping concentration frontal organ spare edge termination.Because devices such as JBS, SBD, MPS are harsh to the requirement at terminal; High to the surface charge susceptibility; The utility model provides the guard ring structure that forms the P+ district in the P trap; And this structure applications formed in the inner P+ ring of MPS, JBS, the utility model claims that this structure is a kind of improved mixed-rectification diode structure.
Description of drawings
Fig. 1 is a kind of improved mixed-rectification diode structure device architecture sketch map of the utility model;
Fig. 2 is common junction barrier schottky diode device architecture sketch map;
Fig. 3 is a kind of improved mixed-rectification diode structure device of the utility model and the comparison of common junction barrier schottky diode device electric breakdown strength characteristic;
Fig. 4 is a kind of improved mixed-rectification diode structure device of the utility model and the comparison of common junction barrier schottky diode device forward conduction characteristic;
Fig. 5 is a kind of improved mixed-rectification diode structure device of the utility model and the comparison of common junction barrier schottky diode device output capacitance.
Embodiment
For example the utility model is done description in more detail below in conjunction with accompanying drawing:
With reference to Fig. 1, a kind of improved mixed-rectification diode structure of the utility model.Comprise N
+Substrate zone 100, N type drift region 101, active area knot P
+Part 102, active area knot P part 103, first's anode electrode 104, cathode electrode 105, silicon dioxide layer 106, second portion anode electrode 107.Its characteristic is at N
+Extension forms N on the substrate zone 100
+ Substrate zone 100, oxidation then, photoetching utilize injection, diffusion technology, are formed with source region knot P part 103, active area knot P according to this
+ Part 102; Active area knot P part 103 is surrounded by source region knot P
+Part 102; The doping content of active area knot P part 103 is lower than active area knot P
+The doping content of part 102; The metal of first's anode electrode 104 and cathode electrode 105 contacts with N type drift region 101 and is ohmic contact, second portion anode electrode 107 and active area knot P
+Part 102 contacts Schottky contacts with active area knot P part 103, and first's anode electrode 104 and second portion anode electrode 107 short circuits.Play after adjacent depletion region is communicated with and suppress Schottky contact barrier reduction effect and make reverse withstand voltage raising in reverse voltage biasing down; Because the active area of low concentration doping knot P part 103 exists, and proper internal electric field is improved, rather than concentrations makes device withstand voltage improve in knot junction depth place, terminal, and leakage current reduces.According to the requirement of the concrete on state characteristic of device, breakdown characteristics, output capacitance, confirm the doping content and the two-dimensional of N type drift region 101 among Fig. 1, the two-dimensional of silicon dioxide layer 106, active area knot P
+The two-dimensional of part 102, active area knot P part 103.
With reference to Fig. 3; Comparison by a kind of improved mixed-rectification diode structure device electric breakdown strength characteristic of the utility model is visible; With respect to common junction barrier schottky diode device; The utility model device has not only improved withstand voltage but also has reduced leakage current and since introduced new peak electric field point promptly not only the PN junction place peak electric field point is arranged, and tie P at active area
+Also there is the peak electric field point in the edge of part 102; This makes that PN junction knee peak electric field point is lower than common junction barrier schottky diode at identical negative sense bias voltage; Depletion layer has reduced reverse leakage current withstand voltage thicker than common junction barrier schottky diode than hour thickness simultaneously.
With reference to Fig. 4; Comparison by a kind of improved mixed-rectification diode structure device of the utility model and common junction barrier schottky diode device forward conduction characteristic is visible; With respect to common junction barrier schottky diode devices, forward conduction characteristic characteristic does not almost have difference.Because the Schottky contacts area of JBS device does not change than the ratio of PiN junction area, explains that the utility model does not influence the on state characteristic of JBS.
With reference to Fig. 5; Comparison by a kind of improved mixed-rectification diode structure device of the utility model and common junction barrier schottky diode device output capacitance is visible; With respect to common junction barrier schottky diode device, a kind of output capacitance difference of improved mixed-rectification diode structure device is very little, does not surpass an one magnitude; But raise with reverse bias voltage, the utility model device output capacitance is less.Because a kind of improved mixed-rectification diode structure device is also consistent with the same, the inner PiN duct ligation of the junction depth area of common junction barrier schottky diode device; But few charge of the electron quantity of the utility model is less than common JBS, explains that the utility model slightly improves output capacitance.
Above-mentioned is the embodiment of the special act of the utility model, is not in order to limit the utility model.A kind of improved mixed-rectification diode structure device architecture that the utility model provides is equally applicable to other material power semiconductor and MPS etc.In essence that does not break away from the utility model and scope, can do a little adjustment and optimization, the protection range of the utility model is as the criterion with claim.