DE102005041879A1 - Fabrication method for IGBT, has insulation layer between body-zone and drift zone - Google Patents

Abstract

Method for fabricating an IGBT with a drift zone (14) and body -zone (42), involves preparing a semiconductor body (100) which sectionally forms the drift zone (14), fabricating an insulation layer with a layer thickness less than 50 nm, depositing the semiconductor layer (400) on exposed zones of a first face of the semiconductor body (100), fabricating the body-zone (42) and a doped source zone (43), and fabricating a gate-electrode (52) adjacent to the body-zone (42). An independent claim is given for an IGBT.

Description

The The present invention relates to a process for producing a IGBT with a body zone and a drift zone, between which a section Insulation layer is arranged.

Such IGBTs, which are also referred to as SOI-IGBT are, for example, in DE 195 22 161 C2 , of the DE 197 41 972 C1 , of the DE 198 01 093 A1 or the US 5,396,087 described.

at an IGBT are in addition to the body zone and the drift zone in known There is a source zone and a drain zone, of which the Body zone between the source zone and the drift zone and the drift zone is arranged between the body zone and the drain zone. The source zone and the drift zones are usually n-doped in an IGBT and are also referred to as n-emitter and n-base while the Body zone and the drain zone usually p-doped and as p-base and p-emitter. Adjacent to the body zone is a gate electrode disposed in dielectric opposition to Semiconductor zones is isolated and used to control a conductive Inversion channels in the body zone between the source zone and the Drift zone is used. In the case of a conductive component, electrons flow from the source zone over the Inversion channel in the body zone and the drift zone to the drain zone, while holes from the drain zone over the drift zone will flow to the body zone, which will be shorted to the source zone is.

The arranged in sections between the body zone and the drift zone Insulation layer serves to "steer" the hole current and is arranged so that the holes predominantly in the region of the inversion channel enter the body zone. The se holes provide in the drift zone for one higher conductivity of the component.

These Insulation layer buried in the semiconductor body arranged is, in which the component zones are formed, but so far only very complex to realize.

A possibility for the preparation of this insulating layer is the so-called SIMOX process. at this procedure is first Oxygen to the desired Position of the insulating layer implanted in the semiconductor body. This implantation process is followed by a temperature step to bury a semiconductor oxide layer in the semiconductor body as an insulating layer, and to irradiation damage in the about that Heal lying semiconductor layer.

Another method for producing a buried insulating layer is with reference to FIGS US 4,522,662 in that a laterally limited insulating layer is applied to a first semiconductor layer and then an epitaxy process is carried out by which a semiconductor material monocrystalline grows on exposed surfaces of the semiconductor layer and, starting from the exposed surfaces of this semiconductor layer, overgrows the insulating layer from the edges thereof. The problem here is that voids can arise at the points where the growing from the edges ago sections of the semiconductor layer meet. To avoid this problem is in the aforementioned US 4,522,662 describes a complex epitaxial process in which the process parameters for the epitaxial deposition of the semiconductor layer must be changed several times.

aim The present invention is a process for the preparation an IGBT with a section between a drift zone and a body layer arranged isolation layer available which is easily realizable and which are the ones mentioned above Disadvantages not. The aim of the invention is also a IGBT produced by this method put.

The inventive method for producing an IGBT provides a semiconductor body for disposal to provide, in sections, the later drift zone of the device forms and which has a first and a second side. On the first side of the semiconductor body becomes an insulating layer with a layer thickness of less manufactured as 50nm, which is then structured in such a way that it is partially removed from the first page and that at least a portion of the insulating layer remains.

On exposed portions of the first side of the semiconductor body and the at least a portion of the insulating layer is by means of an epitaxial process then deposited a semiconductor layer, the monocrystalline on exposed areas of the first side of the Semiconductor body and grows up the portion of the insulation layer. This procedure is based on the knowledge that by means of an epitaxy without additional activities a monocrystalline semiconductor layer on a thin insulating layer, So an insulation layer with layer thicknesses of less than 50nm, can be made when the insulation layer in the lateral direction is limited, so if these edges in which they are attached to a monocrystalline semiconductor material borders.

Of the Invention is also the realization that so-called SOI-IGBT already very much thin insulation layers between the drift zone and the body zone are sufficient to the hole current suitable to steer. The thickness of this insulating layer, at Use of silicon as a semiconductor material, for example Silica exists, be wearing preferably less than 20nm and can withstand voltage own, which is less than 1V, since the voltage load in the area of the device, placing this insulation layer between the drift zone and the body zone is very small.

To Depositing the single crystal semiconductor layer on the exposed ones Regions of the semiconductor body and the laterally limited insulating layer close Further process steps for the preparation of the body zone, and a complementary to the Body zone doped source zone in the semiconductor layer. Of Further becomes a gate electrode manufactured, which is arranged adjacent to the body zone and isolated by means of a gate dielectric with respect to the body zone is.

The inventive method is suitable both in the context of producing planar IGBTs as well as in connection with the production of trench IGBTs. In a planar IGBT, the gate electrode is above the Semiconductor body remote from the monocrystalline semiconductor layer. To realize a trench IGBT, the gate electrode is in one Trench produced, which faces away from the semiconductor body Side extends into the semiconductor layer and in one lateral direction spaced from the insulating layer is.

The The present invention will be explained in more detail below with reference to figures.

1 illustrates the inventive method for producing a planar IGBT based on cross-sections through the device during various process steps.

2 shows a plurality of similar transistor cell having planar IGBT in side view in cross section.

3 illustrates the inventive method for producing a trench IGBT based on cross-sections through the device during various process steps.

In denote the figures, unless otherwise indicated, like reference numerals same component areas with the same meaning.

A first embodiment of the method according to the invention, which is used to produce a planar IGBT, is described below with reference to FIG 1 explained.

The starting point of the manufacturing process is referring to 1a the provision of a semiconductor body 100 who is a first page 101 hereafter referred to as front side and a second side 102 , which will be referred to as the back side, has. This semiconductor body 100 , which partially forms the later drift zone of the IGBT, may have a basic doping of the first conductivity type throughout, this basic doping corresponding to the doping of the later drift zone of the IGBT.

Alternatively it is possible to use a semiconductor body 100 to provide that has two differently doped semiconductor layers, namely a first semiconductor layer 110 and a second semiconductor layer 120 as dashed in 1a is shown. The first semiconductor layer 110 forms the front side 101 and is doped with dopant atoms of the first conductivity type, while the second semiconductor layer 120 is doped with dopant atoms of the second conductivity type and the back 102 of the semiconductor body 100 forms. The second semiconductor layer 120 is, for example, a semiconductor substrate to which the first semiconductor layer may be applied as an epitaxial layer. The second semiconductor layer 120 is more heavily doped than the first semiconductor layer 110 and forms a later drain zone of the IGBT, while the first semiconductor layer 110 sections forms the drift zone of the later IGBT.

For the further explanation, it is initially assumed that the semiconductor body 100 has a homogeneous Grunddotierung the first conductivity type.

Referring to 1b will be on the front 101 of the semiconductor body 100 an insulation layer 200 which has a layer thickness d of less than 50 nm, preferably less than 20 nm. This insulating layer is, for example, an oxide layer which, when silicon is used as the material for the semiconductor body 100 made of silicon oxide (SiO ₂ ). The production of this insulation layer 200 can by thermal oxidation of the semiconductor body 100 or by depositing an oxide, for example TEOS (tetraethoxysilane).

This isolation layer 200 is referred to 1c subsequently structured in such a way that the insulation layer 200 sections of areas of the front 101 is removed and that an isolation section 20 on the front side 101 remains. The structuring of the insulation layer 200 is done using a mask 300 and an etching process. The mask 300 covers during the etching process, the sections of the insulating layer 200 starting as the insulation layer section 20 on the front side 101 should be preserved. The etching method is, for example, an anisotropic etching method that is selected such that the semiconductor body 100 serves as etch stop layer.

Referring to 1d will after removing the mask 300 a semiconductor layer 400 epitaxially on exposed areas of the first page 101 the semiconductor body and the insulating layer portion 20 deposited. The semiconductor layer 400 grows monocrystalline on the semiconductor body 100 and because of the small layer thickness d of the insulating layer section 20 also monocrystalline on the insulation layer section 20 on. The semiconductor layer 400 is preferably deposited as a doped semiconductor layer, whose doping concentration preferably the doping concentration of the basic doping of the semiconductor body 100 equivalent. The deposited semiconductor layer 400 forms in a manner yet to be explained in sections, the drift zone of the IGBT.

1e shows the device after performing further process steps in which a dielectric layer 51 on a subsequently referred to as the front surface 401 the semiconductor layer 400 and an electrode layer 52 on the dielectric layer 51 is applied and in which the obtained layer stack 51 . 52 is structured such that it is above the insulating layer section 20 one to the front 401 reaching recess 54 having. The structuring of the layer stack with the dielectric layer 51 and the electrode layer 52 can be done in a well-known manner using a masked etching process. A mask 301 for carrying out such an etching process is in 1e shown in dashed lines.

The layer stack with the dielectric layer 51 , which forms the later gate dielectric, and the electrode layer 52 , which forms the later gate electrode, and optionally with the still applied to the layer stack used to structure it 301 serves as a mask for subsequent doping steps, in which a body zone 42 of the second conductivity type in the semiconductor layer 400 and a source zone 43 of the first conductivity type within the body zone 42 is produced.

1f shows the device in cross section after performing these doping steps. During the doping process, dopant atoms become over the front 401 in the area of the recess 54 of the layer stack in the semiconductor layer 400 implanted. This implantation can be done with different implantation energies to different dopant atoms in the semiconductor layer 400 to implant. The implantation process is followed by a temperature step in which at least the semiconductor layer 400 is heated to a predetermined temperature to activate and diffuse the implanted dopant atoms. In a similar way, the source zone 43 produced by using an implantation method and a subsequent diffusion method. The duration of the diffusion process for the production of the source zone 43 and / or the temperature used is less than the duration of the diffusion process for the preparation of the body zone 42 and / or the temperature used. This ensures that the source zone 43 in the lateral direction of the semiconductor layer 400 less far below an edge of the recess 54 of the shift stack 51 . 52 diffuses, leaving the body zone 42 in sections to the front 401 the semiconductor layer 400 enough.

Optionally, the production of the body zone is such that even below the insulation layer section 20 in the semiconductor body 100 a semiconductor zone 11 of the second conductivity type, which forms part of the body zone. The production of this semiconductor zone 11 can be done by dopant atoms of the second conductivity type at sufficiently high implantation energies across the front 401 the semiconductor layer 400 through the insulation layer section 20 into the area of the later partial zone 11 implanted or diffused into the body zone.

The production of the body zone 42 respectively. 11 based on the position of the insulating layer portion 20 can be done such that the body zone 42 in the lateral direction of the semiconductor layer 400 has a larger dimension than the insulating layer portion 20 such that the insulation layer section 20 within the semiconductor layer 400 completely from the body zone 42 is surrounded. The production of the body zone 42 However, it can also be done so that the insulation layer section 20 in a lateral direction over the body zone 42 enough. The dimensions of the body zone 42 in the lateral direction of the semiconductor layer 400 are significantly determined by the dimensions of the recess in the layer stack 51 . 52 and the duration of the diffusion process during the doping process, so that the position of the body zone 43 . 11 based on the position of the insulating layer section 20 is adjustable via these parameters.

A in the lateral direction of the semiconductor layer 400 to the body zone 42 subsequent section 41 the semiconductor layer 400 having a doping, that of the basic doping of the semiconductor layer 400 corresponds, forms part of the later drift zone of the device.

1g shows the device after performing further process steps to complete the device. In these process steps, a further insulation layer 53 on the patterned electrode layer 52 applied. This further insulation layer 53 fills the recess 54 of the layer stack or covers at least the front 401 the semiconductor layer 400 and the electrode layer 52 laterally in the recess 54 , Also, in the area of the recess 54 of the layer stack with the dielectric layer 51 and the electrode layer 52 a contact hole made, which through the further insulation layer 53 and the source zone 43 into the body zone 42 enough. The production of this contact hole is such that portions of the insulating layer 53 remain on sidewalls of the contact hole to a subsequent in this contact hole and on the surface of the insulating layer 53 prepared source electrode 61 opposite to the electrode layer 52 to isolate. The source electrode 61 closes the source zone 43 and the body zone 42 short in a known manner.

If the semiconductor body 100 At the beginning of the manufacturing process has only a basic doping of the first conductivity type, the completion of the device is still the production of a drain zone 12 in the area of the back 102 required. The production of this drain zone 12 For example, by implantation of dopant atoms of the second conductivity type across the backside 102 respectively. Preferably, the semiconductor body becomes 100 before implantation of these dopant atoms starting from the backside 102 abraded or thinly ground, thereby reducing the dimensions of the drift zone of the device. The drift zone of the component is in sections by such areas of the semiconductor body 100 formed, having its Grunddotierung the first conductivity type.

In a semiconductor body 100 , which already at the beginning of the process a highly doped semiconductor layer 120 of the second conductivity type and a weakly doped semiconductor layer deposited thereon 110 of the first conductivity type, as shown in dashed lines in FIG 1a is shown forms the highly doped semiconductor layer 120 of the second conductivity type, the drain region 12 of the component.

The drift zone of the IGBT is covered by the section 41 the semiconductor layer 400 moving in a lateral direction to the body zone 42 followed, and by a Grunddotierung having section 14 of the semiconductor body 100 or (in a manner not shown) by the weakly doped semiconductor layer 110 educated.

Optionally, there is also the possibility between the drain zone 12 of the second conductivity type and the one section 14 the drift zone 14 . 41 provide a field stop zone of the first conductivity type, which is higher than the drift zone 14 is doped. The fabrication of this field stop zone can also be achieved by implantation of dopant atoms over the backside 102 respectively.

The semiconductor zones of the first conductivity type, ie the source zone 43 and the drift zone 41 . 14 are usually n-doped semiconductor zones in an IGBT, while the semiconductor zones of the second conductivity type, ie the body zone 42 and the drain zone 12 are usually p-doped semiconductor zones. The component is conductively driven when such a drive potential to the gate electrode 52 that is created in that between the source zone 43 and the drift zone 41 arranged section of the body zone 42 forms an inversion channel. When a positive voltage is applied between the drain zone 12 and the source zone 43 an electron current flows from the source zone 43 about the body zone 42 and the drift zone 41 . 14 to the drain zone 12 , In the reverse direction, a hole current flows out of the drain zone 12 over the drift zone 14 . 41 to the body zone 42 that with the sorce electrode 43 shorted. The insulation layer section 20 causes here that holes predominantly only in a lateral direction to the body zone 42 whereby the hole concentration in particular in the region of the drift zone 41 . 14 is increased, in which the accumulation channel is formed, which leads to an overall reduction in the on resistance of the device.

The 1a to 1g show the component only partially during the individual process steps for its production. Preferably, for the realization of the IGBT a plurality of in 1g illustrated structures each having an insulating layer section 20 , a body zone 42 , a source zone 43 and a gate electrode 52 produced.

2 shows a section with two such, also referred to as transistor cells structures in cross section. In the lateral direction between the body zones 42 This transistor cell is preferably a semiconductor zone 61 of the second conductivity type present to the front 401 the semiconductor layer 400 enough. This semiconductor zone 61 serves to avoid recombination of holes in the drift zone 41 . 14 with electrons at the interface to the insulating layer 51 ie it prevents holes from entering this interface 51 can reach. At this interface, the holes would rapidly recombine with electrons, because there is a higher recombination rate. This increased recombination would increase the hole concentration in the drift zone 41 . 14 reduce and thereby the conductivity of the drift zone 41 . 14 reduce.

The gate electrodes 52 the individual transistor cells are electrically conductively connected to each other, wherein the gate electrodes 52 two adjacent transistor cells may be formed by an electrode portion whose distance from the front 401 varies so that it continues in the section between the two transistor cells to the front 401 is spaced as in the areas of the body zones 42 in which an accumulation channel is to be created when a drive potential is applied to the gate electrode.

Based on 3a to 3e An embodiment of the method according to the invention for producing a trench IGBT is explained below.

Referring to 3a is in the manner already explained, an insulating layer with a layer thickness d of less than 50nm, preferably less than 20nm, on the front 101 a semiconductor body 100 applied and then structured such that at least one insulation layer section 20 arises. 3a shows two such insulation layer sections 20 which are spaced apart in the lateral direction.

Referring to 3b then becomes a semiconductor layer 400 epitaxially on the front 101 and the insulation layer sections 20 deposited. This semiconductor layer 400 is a doped semiconductor layer, which in a homogeneously doped, a basic doped semiconductor body 100 is doped complementary to the basic doping of the semiconductor body 100 and the sections forms the later body zone of the device.

The semiconductor body 100 can like that with the basis of 1 explained methods instead of a homogeneous basic doping two complementary doped semiconductor layers 110 . 120 exhibit. The below the front 101 of the semiconductor body 100 arranged first semiconductor layer 110 forms in this case the later drift zone of the device. The complementary to this semiconductor layer 110 doped, on this first semiconductor layer 110 applied semiconductor layer 400 forms in sections the later body zone of the component.

3c shows the device in side view in cross section after performing further process steps in which a semiconductor zone 43 ' of the first conductivity type below the front 401 the semiconductor layer 400 will be produced. The production of this semiconductor zone 43 ' , which forms in sections the later source zone of the IGBT, is done by applying a mask 302 and by subsequently implanting dopant atoms into the regions of the semiconductor layer 400 passing through the mask 302 exposed. The semiconductor zone 43 ' is above a region of the semiconductor body 100 produced in which no insulation layer section 20 is arranged. This corresponds to the section of the front 101 of the semiconductor body 100 prior to depositing the semiconductor layer 400 exposed. In the lateral direction of the semiconductor layer 400 the semiconductor zone extends 43 ' of the first conductivity type over the insulation layer portions 20 in addition, ie the semiconductor zone 43 ' overlaps the insulation layer sections 20 in the lateral direction, that is over the edges of this insulation layer 20 ,

3d shows the device after further process steps in which a trench 402 is made, extending in a vertical direction from the front 401 in the semiconductor layer 400 hineinerstreckt. This trench divides the semiconductor zone 43 ' in two sections 43 , which form the later source zone of the component and extends in the example in the vertical direction to the boundary between the semiconductor body 100 and the semiconductor layer 400 enough.

The adjacent adjacent sidewalls of the trench sections 42 the semiconductor layer 400 form the later body zone of the component. The ditch 402 is made so that its dimensions in the lateral direction are such that side walls of the trench 402 spaced apart in the lateral direction to the insulating layer sections are arranged. This leaves a continuous semiconductor region of the later body zone 42 between the later source zones 43 and the semiconductor regions of the semiconductor body 100 in which an inversion channel can form after producing a gate electrode.

3e shows the device after performing further, basically known method steps, through which a gate electrode 52 in the ditch 402 is made by a gate dielectric 51 opposite to the semiconductor layer 400 or the semiconductor body 100 is isolated. Also, on the front 401 a source electrode 61 applied to the source zone 43 and the body zone 42 short-circuits and through a further insulation layer or dielectric layer 55 opposite the gate electrode 52 is isolated.

The structure of the device in the region of the rear side of the semiconductor body 100 can the structure of the previously previously using the 1g and 2 explained components correspond. The drain zone 12 of the second conductivity type can in the manner already explained by implantation of dopant atoms on the back 102 of the semiconductor body 100 take place, with the possibility exists, the semiconductor body 100 before making the drain zone 12 starting from the back 102 to thinly grind.

Optionally, the possibility exists in the manner already explained a field stop zone 13 produce in the area of the back of the device.

The drift zone 14 of the device is through the regions of the semiconductor body 100 formed after making the drain zone 12 and optionally the field stop zone 13 still have the basic doping.

Of course, referring to 3a also the possibility of making available already at the beginning of the method a semiconductor body having two differently doped layers, namely a layer 120 of the second conductivity type in the region of the back, which forms the later drain zone 12 , and a layer applied on this layer 110 of the first conductivity type, the later drift zone 14 of the component forms.

3e shows only a transistor cell of the trench IGBT according to the invention. Of course, the component may comprise a multiplicity of such transistor cells arranged at a distance from one another in the lateral direction. The individual cells may be elongated in the direction perpendicular to the plane of the drawing shown, ie be formed strip-shaped. Of course, any further, in IGBTs basically known cell geometries are applicable. It should be noted that the insulation layer section 20 each adapted to the geometry of the body zone 42 in a planar IGBT and adapted to the geometry of the gate electrode 52 produced at a trench GBT.

d

layer thickness the insulation layer

11

section the body zone, semiconductor zone of the second conductivity type

12

Drain region, Semiconductor layer

13

Field stop zone

14

Drift zones, Semiconductor layer

20

Insulation layer section

21

edge of the insulation section

41

Drift region

42

Body zone

43

Source zone

43 '

Semiconductor zone of the first conductivity type

51

dielectric layer, Gate dielectric

52

Electrode layer, Gate electrode

53

insulation layer

55

insulation layer

61

Source electrode

61

Semiconductor zone of the second conductivity type

100

Semiconductor body

101

front of the semiconductor body

102

back of the semiconductor body

200

insulation layer

300

mask

400

Semiconductor layer

401

front the semiconductor layer

402

Digging the semiconductor layer 400

Claims (13)

Method for producing an IGBT with a drift zone ( 14 ) of a first conductivity type and a section of the drift zone ( 14 ) subsequent body zone ( 42 ) of a second conductivity type and with a section between the body zone ( 42 ) and the drift zone ( 14 ) arranged insulation layer ( 20 ), comprising the following method steps: - providing a semiconductor body ( 100 ), which sections the drift zone ( 14 ) and a first and a second page ( 101 . 102 ), - producing an insulation layer ( 200 ) with a layer thickness (d) smaller than 50 nm on the first side ( 101 ) of the semiconductor body ( 100 ) and structuring the insulation layer such that it is partially separated from the first side ( 101 ) and that at least one insulation layer section ( 20 ), - depositing a semiconductor layer ( 400 ) on exposed areas of the first page ( 101 ) and the at least one section ( 20 ) of the insulation layer ( 200 ) by means of an epitaxy process, - production of the body zone ( 42 ) and one complementary to the body zone ( 42 ) doped source zone ( 43 ) in the semiconductor layer ( 400 ), - producing a gate electrode ( 52 ), which are adjacent to the body zone ( 43 ) is arranged and by means of a dielectric ( 53 ) opposite the body zone ( 42 ) is isolated. Method according to Claim 1, in which the layer thickness of the insulating layer ( 200 ) is less than 20nm. Method according to Claim 1 or 2, in which the body zone ( 42 ) is manufactured in such a way that it is partially up to one side ( 401 ) of the semiconductor layer ( 400 ) and in which the gate electrode ( 52 ) above this page ( 401 ) of the semiconductor layer ( 400 ) will be produced. Method according to Claim 3, in which the semiconductor layer ( 400 ) is a semiconductor layer of the first conductivity type and for the production of the body zone ( 43 ) in an area above the section ( 20 ) of the insulating layer is doped with dopant atoms of the second conductivity type. Method according to Claim 1 or 2, in which the semiconductor layer ( 400 ) is a semiconductor layer of the second conductivity type, which forms the body zone of the IGBT and has the following further method steps: - producing at least one trench ( 402 ) which is spaced in a lateral direction from the insulating layer portion (FIG. 20 ) from one side ( 401 ) in the semiconductor layer ( 400 ), forming a dielectric layer ( 51 ) on side walls and a bottom of the at least one trench ( 401 ), and - producing a gate electrode ( 52 ) on the dielectric layer ( 51 ) in the trench ( 402 ). Method according to claim 5, wherein the trench ( 401 ) is made such that it reaches as far as an interface between the semiconductor layer ( 400 ) and the semiconductor body ( 100 ) or below this interface. Method according to one of the preceding claims, in which the semiconductor body ( 100 ) a first semiconductor layer ( 110 ) of the first conductivity type, the sections of the drift zone ( 14 ), in the area of the first page ( 101 ) of the semiconductor body, and in which the semiconductor body ( 100 ) a second semiconductor layer ( 120 ) of the second conductivity type, which forms in sections the one drain zone of the IGBT, in the region of the second side ( 102 ) of the semiconductor body ( 100 ) having. Method according to one of claims 1 to 6, wherein a drain zone ( 12 ) of the second conductivity type in the region of the second side ( 102 ) of the semiconductor body ( 100 ) is produced by implantation of dopant atoms of the second conductivity type. Method according to Claim 8, in which the semiconductor body ( 100 ) before making the drain zone ( 12 ) starting from the second side ( 102 ) is partially removed. IGBT, comprising: a semiconductor body ( 100 . 400 ) with a drift zone ( 14 ) of a first conductivity type, a source zone ( 43 ) of a first conductivity type, a body zone ( 42 ) of a second conductivity type, which adjoin the drift zone ( 14 ), - a gate electrode ( 52 ) disposed adjacent to the body zone and through a dielectric layer ( 51 ) opposite the body zone ( 42 ), the source zone ( 43 ) and the drift zone ( 14 ; 14 . 11 ) is isolated. An insulation layer ( 20 ), the sections between the body zone ( 42 ) and the drift zone ( 14 ), characterized in that a thickness of the insulating layer ( 20 ) in one direction from the drift zone ( 14 ) to the body zone ( 43 ) is less than 50nm. IGBT according to claim 10, wherein the thickness (d) of the insulating layer ( 20 ) is less than 20nm. IGBT according to claim 10 or 11, wherein the body zone ( 42 ), the source zone ( 43 ) and the drift zone ( 14 ) in sections up to a first page ( 401 ) of the semiconductor body ( 100 . 400 ) and in which the gate electrode ( 52 ) above this page ( 401 ) is arranged. IGBT according to Claim 10 or 11, in which the gate electrode ( 52 ) is arranged in a trench extending from one side ( 401 ) in a vertical direction into the semiconductor body ( 100 . 400 ) and in a lateral direction spaced from the insulating layer (FIG. 20 ) is arranged.