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Double step field plate terminal based 4H-SiC Schottky diode and manufacturing method thereof

A technology of Schottky diodes and manufacturing methods, which is applied in semiconductor/solid-state device manufacturing, electrical components, electric solid-state devices, etc., can solve problems such as low breakdown voltage and uneven electric field distribution of passivation layer, and achieve improved breakdown voltage, avoiding premature breakdown, and increasing the length

Inactive Publication Date: 2016-10-26
XIDIAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In fact, the low breakdown voltage of Schottky diodes with traditional field plate terminals is mainly due to the large electric field at the edge of the Schottky contact and the uneven electric field distribution of the passivation layer on both sides of the Schottky contact.

Method used

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  • Double step field plate terminal based 4H-SiC Schottky diode and manufacturing method thereof
  • Double step field plate terminal based 4H-SiC Schottky diode and manufacturing method thereof
  • Double step field plate terminal based 4H-SiC Schottky diode and manufacturing method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] In Example 1, a 4H-SiC Schottky diode with a double-step field plate terminal with two steps with a thickness of 100 nm and 250 nm from top to bottom was fabricated.

[0039] Step 1. Select 4H-SiC substrate for standard RCA cleaning.

[0040] 1a) Choose a diameter of 2 inches and a doping concentration of 1×10 18 cm -3 Of N + 4H-SiC substrate;

[0041] 1b) Clean the selected SiC substrate with a mixed solution of 1:1:5 hydrochloric acid, hydrogen peroxide, and deionized water for 5 minutes to remove metal oxides, hydroxides and active metals on the substrate surface Impurities

[0042] 1c) Soak the cleaned substrate in a mixture solution of hydrogen fluoride and deionized water with a ratio of 1:10 for 30 seconds to remove natural oxides on the surface of the substrate;

[0043] 1d) Dry the cleaned substrate with nitrogen.

[0044] Step 2: Growing an epitaxial layer on the front surface of the substrate.

[0045] Use CVD method to grow the same type of N on the front surface of th...

Embodiment 2

[0085] Example 2: Fabrication of a 4H-SiC Schottky diode with a double-step field plate terminal with two steps with a thickness of 300 nm and 200 nm from top to bottom.

[0086] Step 1, select 4H-SiC substrate for standard RCA cleaning.

[0087] The specific implementation of this step is the same as step 1 of embodiment 1.

[0088] Step 2: Growing an epitaxial layer on the front surface of the substrate.

[0089] The specific implementation of this step is the same as step 2 of embodiment 1.

[0090] Step 3: Prepare ohmic contacts on the back of the substrate.

[0091] The specific implementation of this step is the same as step 3 of embodiment 1.

[0092] Step 4: etch the surface of the epitaxial layer to form alignment marks.

[0093] The specific implementation of this step is the same as step 4 of embodiment 1.

[0094] Step 5, deposit SiO on the surface of the epitaxial layer where the alignment mark is formed 2 Passivation layer.

[0095] 5.1) The PECVD method uses the following proc...

Embodiment 3

[0113] Embodiment 3: Fabrication of two stepped 4H-SiC Schottky diodes with a thickness of 300 nm from the top to the bottom of the double step field plate terminal.

[0114] Step A, select 4H-SiC substrate for standard RCA cleaning.

[0115] The specific implementation of this step is the same as step 1 of embodiment 1.

[0116] Step B, growing an epitaxial layer on the front surface of the substrate.

[0117] The specific implementation of this step is the same as step 2 of embodiment 1.

[0118] Step C, preparing an ohmic contact on the back of the substrate.

[0119] The specific implementation of this step is the same as step 3 of embodiment 1.

[0120] Step D, etching the surface of the epitaxial layer to form alignment marks.

[0121] The specific implementation of this step is the same as step 4 of embodiment 1.

[0122] Step E, depositing SiO on the surface of the epitaxial layer with alignment marks 2 Passivation layer.

[0123] First, set the PECVD process conditions as follows:

...

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Abstract

The invention discloses a double step field plate terminal based 4H-SiC Schottky diode, which mainly solves the problem that the breakdown voltage of a conventional double step field plate terminal based 4H-SiC Schottky diode is less than 1500V. The Schottky diode comprises an N + 4H-SiC substrate (1) and an N- 4H-SiC epitaxial layer (2). The back of the substrate is provided with an ohmic contact (3). The two sides of the epitaxial layer surface are provided with SiO2 passivation layers (4). The middle part of the epitaxial layer surface is provided with a metal field plate terminal (5). The schottky diode is characterized in that the passivation layers (4) and field plate terminal (5) are of a double step shape; the thickness of the double step passivation layers is identical to that of the double step field plate terminal, and the total thickness ranges from 350nm to 600nm. Because the field plate terminal is designed to be of a double step shape, the breakdown voltage of the 4H-SiC Schottky diode can reach 1800V or above; therefore, the diode breakdown ability improves, making it suitable for fabrications of large power integrated circuits.

Description

Technical field [0001] The invention belongs to the technical field of microelectronic devices, and relates to a third-generation wide band gap semiconductor material 4H-SiC high-voltage Schottky diode and a manufacturing method thereof, and can be used for the preparation of high-power integrated circuits. Background technique [0002] Due to the advantages of high switching frequency, lower forward voltage, and high reverse breakdown voltage, Schottky diodes are indispensable as high-power devices in the fields of electric power, aviation, military, communications, and energy. With the continuous development of semiconductor technology, higher requirements have been placed on the performance of Schottky diodes. The traditional silicon-based Schottky diode realizes the rectification characteristics of the device through the contact of N-type Si material and precious metals such as gold, silver, aluminum, and platinum. Due to the narrow band gap of silicon material and the high ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L29/872H01L29/40H01L23/31H01L21/329
CPCH01L29/872H01L23/3171H01L29/402H01L29/6606
Inventor 刘红侠李伟
Owner XIDIAN UNIV
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