CN2217264Y - High speed tunnel insulated gate bipolar transistor - Google Patents

Abstract

The utility model belongs to the field of semiconductor devices. The utility model discloses a new high-speed bipolar transistor with insulated grids and tunnel pumps (TIGBT). Because the utility model adopts silicon-wafer direct-bond (SDB) materials which comprise tunnel pumps to replace high-resistance anisotropic thick epitaxial silicon wafers in conventional IGBT to serve as substrates, the lower part of a substrate (10) is made from P <+> high-concentration silicon-single-crystal materials (9) and the upper part is made from N <-> low-concentration silicon-single-crystal materials (6). The utility model is easy to be processed, and can lower cost. Further, compound tunnel junctions in the SDB substrate materials provide quick-release channels for nonequilibrium carriers when the devices are switched off. Therefore, the utility model reduces turn-off time T <off>, enhances speed, and is suitable for manufacturing high-speed TIGBT in full voltage resistant range (hundreds of volts to more than 2000 volts).

Description

Tunnel pump high speed igbt

The utility model belongs to field of semiconductor devices, particularly a kind of power device.

As everyone knows, high-power and high-frequency is the both direction of power device development, and conducting resistance Ron and withstand voltage V in the power device _BWith forward voltage drop V _FWith transient state turn-off time T _OffTwo basic contradictions limited their development.Fa Ming igbt (IGBT) is the representative that electricity is led the modulation type power device in recent years, its cellular construction schematic diagram such as Fig. 1.It utilizes the principle of conductivity modulation effect, has reduced V _FThereby, can reduce Ron and better also overcome Ron and V _BFirst pair of contradiction.Therefore IGBT has input impedance height, no second breakdown, low V _FEtc. advantage, become withstand voltage at the main flow device of 1500V at present both at home and abroad with interior widely used novel power transistor.But the weakness the most outstanding of IGBT is switching speed low (its value is only about 20KHz).The main factor that influences switching characteristic is turn-off time T _Off, people have carried out a series of work for this reason, and the main at present Lifetime Control technology that adopts for example utilizes electron irradiation or neutron irradiation to reduce the life-span of minority carrier so that turn-off time T _OffDescend, or be aided with structural variation again; At P ⁺Anode and N ^-Increase N between the drift region ⁺Resilient coating; Or optimization N ^-With N ⁺The thickness and the concentration of layer; Or optimize cellular (Cell) figure, reduce channel length and cellular spacing and wait and reduce switching time, but this all can make electricity lead modulating action to weaken, cause forward voltage drop V _FIncrease, work as T especially _OffWhen being lower than 0.5 μ s, V _FTo sharply rise, but also be subjected to the restriction of technology.Therefore, high-speed and low-loss is the principal contradiction that above-mentioned second pair of contradiction just becomes IGBT; Also have a problem in addition in the IGBT making, its backing material adopts P ⁺/ N ^-The thick epitaxial wafer of opposite sex High Resistivity Si, this is processing difficulties not only, and the production cost height (1 thickness of import is that 3 inches agreements that contracts a film or TV play to an actor or actress of 100 μ m need about 800 yuan, and the epitaxial wafer quality of domestic production at present still can not meet the demands fully), epitaxial loayer can not be done too thickly in addition, thereby is difficult to make the device of Withstand voltage layer greater than 2000V.Thereafter, Toshiba Corp utilized silicon direct bonding (Silicon-wafer Di-rect Bonding is called for short SDB) material to replace the thick epitaxial wafer of different in nature High Resistivity Si as substrate in 1986, make high pressure IGBT, but its speed was still lower; Siemens in 1992 has reported that a kind of utilize the silicon single crystal back side to inject to make withstand voltage be the new method of 2000 volts IGBT, but its turn-off time is still very long, and its back side injects and need employing laser annealing mode, thereby the expensive efficient of cost is low; Particularly, this method then can be because of N to medium withstand voltage IGBT ^-Single crystalline layer is too thin, is difficult to processing (as withstand voltage 1200 volts, monocrystalline thickness is about 100 microns) and should not adopt.

Above-mentioned two large problems at present IGBT existence, task of the present utility model is to design a kind of IGBT of new construction, make it to overcome the low principal contradiction of conventional lGBT speed, realize high-speed and low-loss, again can work in complete withstand voltage scope (from several hectovolts to greater than 2000V), and manufacture craft is simple, cost is low, to satisfy the urgent need of all types of user to high speed, high withstand voltage IGBT.

The utility model is a kind of tunnel pump high speed igbt (TIGBT), its cellular construction schematic diagram such as Fig. 2.It adopts silicon direct bonding (SDB) material that contains the tunnel pump to replace the conventional thick epitaxial wafer of different in nature High Resistivity Si as substrate 10, and the bottom of this SDB substrate 10 is P type silicon high concentration region (P ⁺) 9, top is n type silicon low concentration region (N ^-) 6, the P by a plurality of high concentrations is arranged between the upper and lower part ⁺7/N ⁺8/P ⁺The layer that 7 alternate zones are formed, N wherein ⁺District 8 and P all around ⁺The P of district 7 and bottom ⁺District 9 forms compound tunnel junction, this tunnel junction especially as a charge pump, when device turn-offs for nonequilibrium electron provides the rapid release passage, thereby reduced turn-off time T _Off, improved the switching speed of IGBT, reduced loss.The N of this tunnel junction ⁺District 8 and P all around ⁺District 7 is the K value at the ratio perpendicular to the area on the sense of current, and the big young pathbreaker of K value influences turn-off time T _OffWith forward voltage drop V _FHeight, its value is chosen as in 0.05～0.5 the scope, N ⁺The shape in district 8 can be square or rectangle or garden shape, N ⁺The area in district 8 is elected to be less size in the scope that technology allows; N at substrate 10 ^-Be shaped on a plurality of unit on the single facet, its number of unit is by the desired load current value decision of this device.Grid 3 and negative electrode 4 are arranged, N on each unit ^-The thickness of single crystalline layer is decided by the withstand voltage height of requirement on devices, as requires withstand voltage height then to choose thick N ^-Single crystalline layer, the withstand voltage low N that approaches that then chooses of requirement ^-Single crystalline layer is with N ^-The grid 3 of each unit and negative electrode 4 are in parallel respectively on the single crystalline layer; The P of substrate 10 ⁺Distinguish on the lower surface of 9 monocrystalline the metallization back as anode 5, thereby constitute tunnel pump high speed igbt (TIGBT).

The utility model has three advantages: adopt the SDB material that contains the tunnel pump to replace the conventional thick epitaxial wafer of different in nature High Resistivity Si as substrate, not only handling ease is easy to produce in batches, greatly reduces cost (substrate of 3 inches sizes of a slice only needs about 200 yuan); And, utilize this backing material to make the T of TIGBT _OffBigger reduction is arranged, the present turn-off time T of the IGBT of 5～35A/1200V in the world _OffRepresentative value be between 0.2～1.5 μ s, and T of the present utility model _OffBe equal to or less than 0.18 μ s, improved speed; Utilize structure of the present utility model, as long as suitably control N in the substrate ^-The thickness of monocrystalline can be made the high speed TIGBT of withstand voltage entirely (hundreds of lying prostrate greater than 2000 volts) scope easily, thereby has expanded the range of application of IGBT greatly, satisfies the urgent need of all kinds of military and civilian's applications.

Accompanying drawing and description of drawings:

Fig. 1: conventional IGBT cellular construction schematic diagram

Wherein: 1-P ⁺Silicon single crystal; 2-N ^-The silicon thick epitaxial layer; 3-grid; 4-negative electrode; 5-anode.

Fig. 2: tunnel of the present utility model pump TIGBT cellular construction schematic diagram

Wherein: 3-grid; 4-negative electrode; 5-anode; 6-N ^-Silicon single crystal; 7-P ⁺The district; 8-N ⁺The district; 9-P ⁺Silicon single crystal.

Embodiment:

Substrate N ^-The resistivity p=80 Ω cm of silicon single crystal, 3 inches polished silicon wafer, thickness is 120 μ m, chooses K value=0.2, utilizes selectivity diffused with boron and phosphorus to form by a plurality of P ⁺District/N ⁺District/P ⁺Distinguish the floor of alternate composition, P ⁺Concentration＞10 in district ²⁰Cm ^-3, N ⁺Concentration＞5 * 10 in district ²⁰Cm ^-3P ⁺The p=0.001 Ω cm of silicon single crystal, thus constitute the SDB substrate that contains the tunnel pump.On this substrate, be manufactured with 10,000 unit shown in Figure 2, the grid and the negative electrode of each unit is in parallel respectively, with P ⁺Do the withstand voltage more than 1200 volts of tunnel pump high speed igbt (TIGBT) that anode constitutes after the silicon single crystal metallization, the transient state turn-off time is below 0.18 microsecond.

Claims (2)

1, tunnel pump high speed igbt (TIGBT) is characterized in that adopting silicon direct bonding (SDB) material that contains the tunnel pump as substrate (10), and the bottom of substrate (10) is P ⁺High concentration silicon single crystal material (9), top are N ^-Low silicon monocrystal material (6) has the P by a plurality of high concentrations between the upper and lower part ⁺(7)/N ⁺(8)/P ⁺(7) alternate regional layer, wherein a N who forms ⁺District (8) and P all around ⁺The P of district (7) and bottom ⁺District (9) forms compound tunnel junction; Substrate (10) top N ^-Be manufactured with a plurality of unit on the single facet, grid (3) and negative electrode (4) are arranged on each unit, grid in each unit (3) and negative electrode (4) is in parallel respectively; Substrate (10) bottom P ⁺Do after the metallization on the single facet that anode (5) constitutes.

2, tunnel pump high speed igbt as claimed in claim 1 (TIGBT) is characterized in that described substrate (10):

(1) N ⁺District (8) can be square, rectangle, garden shape, under the condition that technology allows, and N ⁺The size in district (8) is as far as possible little;

(2) N ⁺District (8) and P ⁺The district (7) perpendicular to the area on the sense of current than being the K value, the scope of its K value is selected between 0.05～0.5;

(3) N ^-The thickness in silicon single crystal district is determined by the withstand voltage height of desired TIGBT.

Images