Field plate trench transistor and method for producing it

• US 7,893,486 B2
• Filed: 01/07/2009
• Issued: 02/22/2011
• Est. Priority Date: 08/31/2005
• Status: Expired due to Fees

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Meyer, Thorsten, Rieger, Walter, Hirler, Franz, Pfirsch, Frank, Klein, Wolfgang
• Primary Examiner(s): Lee; Eugene
• Application Number:
  US12/349,952
• Publication Number:
  US 20090114986A1
• Time in Patent Office: 776 Days
• Field of Search: 257328-330, 257/E29.183
• US Class Current: 257/328
• CPC Class Codes: H01L 27/04 the substrate being a semiconductor body
• CPC Class Codes: H01L 27/0727 in combination with diodes, or capacitors or resistors
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/0878 Impurity concentration or distribution
• CPC Class Codes: H01L 29/404 Multiple field plate structures
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/42368 the thickness being non-uniform
• CPC Class Codes: H01L 29/66734 with a step of recessing the gate electrode, e.g. to form a trench gate electrode
• CPC Class Codes: H01L 29/732 Vertical transistors
• CPC Class Codes: H01L 29/735 Lateral transistors
• CPC Class Codes: H01L 29/7803 structurally associated with at least one other device assemblies H01L25/00; integrated circuits H01L27/00
• CPC Class Codes: H01L 29/7808 the other device being a breakdown diode, e.g. Zener diode
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236
• CPC Class Codes: H01L 29/861 Diodes

Abstract

A field plate trench transistor having a semiconductor body. In one embodiment the semiconductor has a trench structure and an electrode structure embedded in the trench structure. The electrode structure being electrically insulated from the semiconductor body by an insulation structure and having a gate electrode structure and a field electrode structure. The field plate trench transistor has a voltage divider configured such that the field electrode structure is set to a potential lying between source and drain potentials.

Claims

1. A field plate trench transistor having a semiconductor body comprising:

a trench structure;

an electrode structure embedded in the trench structure, the electrode structure being electrically insulated from the semiconductor body by an insulation structure and having a gate electrode structure and a field electrode structure arranged below and/or alongside the gate electrode structure and electrically insulated from the latter; and

a voltage divider which is integrated into the field electrode structure or provided within the mesa zones (adjoining trenches containing field plates), the voltage divider being configured such that the field electrode structure is set to a potential lying between source and drain potentials and/or gate and drain potentials,

wherein the voltage divider is realized as a series circuit comprising a resistor and a Zener diode, the resistor being connected between source potential and the field electrode structure, and the Zener diode being forward-biased between the field electrode structure and drain potential.

2. The field plate trench transistor as claimed in claim 1, wherein the field electrode structure is divided into a plurality of field electrode regions arranged vertically one above another and the voltage divider is divided into a plurality of voltage divider regions, each voltage divider region being electrically connected to a field electrode region or integrated into the latter, so that at least two different field electrode regions are at different potentials.

3. The field plate trench transistor as claimed in claim 1, wherein the different field electrode regions within the trench structure are electrically insulated from one another, and the voltage divider is provided outside the field electrode structure.

4. The field plate trench transistor as claimed in claim 1, wherein the different field electrode regions within the trench structure are electrically connected to one another, and the voltage divider is provided within the field electrode structure.

5. The field plate trench transistor as claimed in claim 4, wherein pn diodes are provided between the field electrode regions, in such a way that the pn diodes are interlinked with one another via the field electrode regions to form a vertically running diode series circuit.

6. The field plate trench transistor as claimed in claim 5, wherein the upper end of the diode series circuit directly adjoins a source metallization layer of the transistor, and the lower end of the diode series circuit directly adjoins a drift zone provided within the semiconductor body.

7. A field plate trench transistor having a semiconductor body comprising:

a trench structure;

means for providing an electrode structure embedded in the trench structure, the electrode structure being electrically insulated from the semiconductor body by an insulation structure means and having a gate electrode structure and a field electrode structure arranged below and/or alongside the gate electrode structure and electrically insulated from the latter; and

means for providing a voltage divider which is integrated into the field electrode structure or provided within the mesa zones (adjoining trenches containing field plates), the voltage divider means being configured such that the field electrode structure is set to a potential lying between source and drain potentials and/or gate and drain potentials,

wherein the voltage divider is realized as a series circuit comprising a resistor and a Zener diode, the resistor being connected between source potential and the field electrode structure, and the Zener diode being forward-biased between the field electrode structure and drain potential.