# US 7,612,344 B1 · Radiation detector and method

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- Number: US 7,612,344 B1
- Document ID: US7612344B1
- Status: Granted
- Kind: B1
- Application number: 12/143,458
- Filed: 2008-06-20
- Granted: 2009-11-03
- Earliest claimed: 2008-06-20
- Assignees: Infineon Technologies Austria AG
- Inventors: Hans-Joachim Schulze; Armin Willmeroth
- Web page: https://patentgrep.com/patent/US7612344B1

## CPC

- H10F 71/00: Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00)
- H10F 71/1221: {comprising polycrystalline silicon}
- H10F 30/21: the devices being sensitive to infrared, visible or ultraviolet radiation
- H10F 77/14: Shape of semiconductor bodies; Shapes, relative sizes or dispositions of semiconductor regions within semiconductor bodies
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

A radiation detector and method. One embodiment provides a radiation detector including a semiconductor body with a first base zone of a first conduction type and with at least one second base zone arranged at least partly in the first base zone, extending in a vertical direction of the semiconductor body and doped complementarily to the first base zone. The method provides a semiconductor substrate. Several epitaxial layers are produced arranged one above another on the semiconductor substrate. The layers in each case include a basic doping of the first conduction type and together with the semiconductor substrate form the semiconductor body. Semiconductor zones of a second conduction type are produced.

## Claims

### Claim 1

A method for producing a radiation detector comprising a semiconductor body with a first base zone of a first conduction type and with at least one second base zone arranged at least partly in the first base zone, extends in a vertical direction of the semiconductor body and is doped complementarily to the first base zone, wherein the method comprises: providing a semiconductor substrate; producing several contiguous epitaxial layers arranged one above another on the semiconductor substrate, each layer comprising a basic doping of the first conduction type and together with the semiconductor substrate form the semiconductor body; and producing semiconductor zones of a second conduction type, complementary to the first conduction type, in the epitaxial layers in such a way that the complementarily doped semiconductor zones are adjacent to one another in a vertical direction and thus form the at least one second base zone.

### Claim 2 (depends on 1)

The method of claim 1, comprising wherein the semiconductor substrate is of the same conduction type as the basic doping of the epitaxial layers.

### Claim 3 (depends on 2)

The method of claim 2, wherein the semiconductor substrate comprises a first semiconductor layer and a second semiconductor layer, doped more lightly than the first semiconductor layer, and wherein the epitaxial layers are applied to the second semiconductor layer.

### Claim 4 (depends on 3)

The method of claim 3, comprising wherein the second semiconductor layer is an epitaxial layer applied to the first semiconductor layer.

### Claim 5 (depends on 1)

The method of claim 1, comprising doping the semiconductor substrate complementarily to a basic doping of the epitaxial layers.

### Claim 6 (depends on 1)

The method of claim 1, wherein producing the complementarily doped semiconductor zones comprises:
implanting dopant atoms of the second conduction type into at least some of the several epitaxial layers after these several epitaxial layers have been produced; and
carrying out at least one thermal process, the temperature and duration of which are chosen such that the implanted dopant atoms indiffuse.

### Claim 7 (depends on 6)

The method of claim 6, comprising choosing the temperature and duration of the thermal process such that the dopant atoms indiffuse as far as a depth corresponding to at least 50% of the thickness of the individual epitaxial layers.

### Claim 8 (depends on 6)

The method of claim 6, comprising carrying out a respective thermal process after producing one or more of the epitaxial layers.

### Claim 9 (depends on 1)

The method of claim 1, comprising producing the basic doping of the individual epitaxial layers during a deposition process.

### Claim 10 (depends on 1)

The method of claim 1, wherein producing the basic doping of the epitaxial layers comprises:
implanting dopants of the first conduction type into the epitaxial layers in each case after producing the latter; and
carrying out at least one thermal process, the temperature and duration of which are chosen such that the implanted dopant atoms indiffuse.

### Claim 11 (depends on 10)

The method of claim 10, comprising choosing the temperature and duration of the thermal process such that the dopant atoms indiffuse as far as a depth corresponding to at least 50% of the thickness of the individual epitaxial layers.

### Claim 12 (depends on 1)

The method of claim 1, comprising:
producing a first connection electrode, which makes contact with the first base zone; and
producing a second connection electrode, which makes contact with the second base zone.

### Claim 13 (depends on 12)

The method of claim 12, comprising:
producing a connection zone of the second conduction type adjacent to the second base zone and doped more highly than the second base zone is produced before the second connection electrode, and
producing the second connection electrode in such a way that it makes contact with the connection zone.

### Claim 14 (depends on 1)

The method of claim 1, comprising producing several semiconductor zones of the second conduction type arranged adjacent to one another in a lateral direction of the epitaxial layers in the epitaxial layers in such a way as to give rise to a second base zone comprising several base zone sections which each extend in a vertical direction of the semiconductor body.

### Claim 15 (depends on 14)

The method of claim 14, comprising producing the base zone sections such that their center-to-center distance is between 20 μm and 160 μm.

### Claim 16 (depends on 14)

The method of claim 14, comprising producing the base zone sections such that a ratio between the maximum net doping concentration of the base zone sections and the net doping concentration of the epitaxial layers is between 2 and 105.

### Claim 17 (depends on 14)

The method of claim 14, comprising producing the base zone sections such that a net dopant dose in a lateral direction running perpendicular to the vertical direction is between 0.1 times and 1000 times the breakdown charge of the semiconductor material used for the epitaxial layers.

### Claim 18

A method for producing a solar cell comprising: providing a semiconductor substrate; producing several contiguous epitaxial layers arranged one above another on the semiconductor substrate, each layer comprising a basic doping of the first conduction type and together with the semiconductor substrate form a semiconductor body including a first base zone of a first conduction type and with at least one second base zone arranged at least partly in the first base zone doped complementarily to the first base zone; and producing semiconductor zones of a second conduction type, complementary to the first conduction type, in the epitaxial layers such that the complementarily doped semiconductor zones are adjacent to one another in a vertical direction and form the at least one second base zone.

### Claim 19

A radiation detector, comprising: a semiconductor body with a first side and with a second side; a first base zone of a first conduction type, arranged in the semiconductor body; at least one second base zone of a second conduction type complementary to the first conduction type, arranged at least partly in the first base zone and extends in a vertical direction of the semiconductor body;
a first connection electrode, connected to the first base zone, and a second connection electrode, which is connected to the second base zone; and
wherein the semiconductor body comprises a semiconductor substrate and several contiguous epitaxial layers applied on the semiconductor substrate, each layer having a basic doping of the first conduction type, wherein the first and the second base zone are arranged at least partly in the epitaxial layers, and wherein the first connection electrode makes contact with the semiconductor substrate at a side remote from the epitaxial layers.

### Claim 20 (depends on 19)

The radiation detector of claim 19, wherein the second base zone comprises several base zone sections arranged at a distance from one another in a lateral direction of the semiconductor body.

### Claim 21 (depends on 20)

The radiation detector of claim 20, comprising wherein a ratio between the maximum net doping concentration of the base zone sections and the net doping concentration of the epitaxial layers is between 2 and 105.

### Claim 22 (depends on 20)

The radiation detector of claim 20, comprising wherein a net dopant dose in a lateral direction running perpendicular to the vertical direction is between 0.1 times and 1000 times the breakdown charge of the semiconductor material used for the epitaxial layers.

### Claim 23 (depends on 19)

The radiation detector of claim 19, comprising wherein the semiconductor substrate is of the first conduction type, and wherein the semiconductor substrate comprises a more highly doped semiconductor layer and, between the more highly doped semiconductor layer and the first and the second base zone, a more lightly doped semiconductor layer of the first conduction type.

### Claim 24

A radiation detector, comprising: a semiconductor body with a first side and with a second side;
a first base zone of a first conduction type, arranged in the semiconductor body; at least one second base zone of a second conduction type complementary to the first conduction type, arranged at least partly in the first base zone and extends in a vertical direction of the semiconductor body;
the semiconductor body including a semiconductor substrate and several contiguous epitaxial layers applied on the semiconductor substrate, each layer having a basic doping of the first conduction type, wherein the first and the second base zone are arranged at least partly in the epitaxial layers, and wherein a first connection electrode makes contact with the semiconductor substrate at a side remote from the epitaxial layers.

### Claim 25 (depends on 24)

The radiation detector of claim 24, extends in vertical direction of the semiconductor between 30 μm and 300 μm.