JP-2026076331-A - Semiconductor device and method for manufacturing a semiconductor device

Abstract

[Problem] To provide a semiconductor device comprising a semiconductor substrate having an upper surface and a lower surface and containing oxygen, in order to accurately adjust the donor concentration of the semiconductor substrate. [Solution] The semiconductor device 100 comprises a semiconductor substrate 10 having an upper surface 21 and a lower surface 23 and containing oxygen, a first peak 133 of hydrogen chemical concentration located on the lower surface side of the semiconductor substrate, and a flat portion located on the upper surface side of the semiconductor substrate below the first peak, containing hydrogen donors, and having a substantially (almost) flat donor concentration distribution in the depth direction of the semiconductor substrate, wherein the oxygen contribution rate, which indicates the proportion of the oxygen chemical concentration of oxygen that contributes to the generation of hydrogen donors, is 1 × 10⁻⁵ or more and 7 × 10⁻⁴ or less, and in the flat portion, the oxygen concentration that contributes to the generation of hydrogen donors is lower than the hydrogen chemical concentration, and the hydrogen donor concentration in the flat portion is 2 × 10¹² / cm³ or more and 5 × 10¹⁴ / cm³ or less. [Selection Diagram] Figure 1

Inventors

• 吉田 浩介
• 吉村 尚
• 瀧下 博
• 内田 美佐稀
• 根本 道生
• 菅沼 奈央
• 窪内 源宜

Assignees

• 富士電機株式会社

Dates

Publication Date

20260511

Application Date

20260217

Priority Date

20191218

Claims (1)

1. In the donor concentration distribution in the depth direction of the semiconductor substrate, a first peak is located on the upper side of the center of the semiconductor substrate, In the donor concentration distribution, a second peak is located on the lower side of the semiconductor substrate, The semiconductor substrate is provided in a predetermined region between the first peak and the second peak, including a depth position in the center of the semiconductor substrate, and comprises a flat portion in which the donor concentration is higher than the bulk donor concentration of the semiconductor substrate and the donor concentration distribution is flat. A semiconductor device in which the total oxygen chemical concentration between the first peak and the second peak is 3 × 10¹⁵ atoms/ cm³ or more and 2 × 10¹⁸ atoms/ cm³ or less.

Description

This invention relates to semiconductor devices and methods for manufacturing them. Conventionally, a technique is known for adjusting the resistance of a semiconductor substrate by injecting hydrogen into a predetermined depth and allowing it to diffuse to form a donor (for example, Patent Document 1). Patent Document 1: U.S. Patent Application Publication No. 2018/0019306 The problem to be solved It is preferable that the donor concentration of the semiconductor substrate be precisely adjusted. General disclosure To solve the above problems, a first embodiment of the present invention provides a semiconductor device having an upper surface and a lower surface, and comprising a semiconductor substrate containing oxygen. The semiconductor device may have a first peak of hydrogen chemical concentration located on the lower surface side of the semiconductor substrate. The semiconductor device may have a flat portion located on the upper surface side of the semiconductor substrate, which contains hydrogen donors, and in which the donor concentration distribution in the depth direction of the semiconductor substrate is substantially (almost) flat. The oxygen contribution rate, which indicates the proportion of the oxygen chemical concentration of oxygen that contributes to the generation of hydrogen donors, may be 1 × 10⁻⁵ or more and 7 × 10⁻⁴ or less. In the flat portion, the oxygen concentration that contributes to the generation of hydrogen donors may be lower than the hydrogen chemical concentration. The hydrogen donor concentration in the flat portion may be 1 × 10¹² / cm³ or more and 5 × 10¹⁴ / cm³ or less. The oxygen contribution rate may be 5 × 10⁻⁴ or less. The oxygen contribution rate may be 1 × 10⁻⁴ or greater. The semiconductor substrate may contain bulk donors. The donor concentration in the flat regions may be higher than the bulk donor concentration. The semiconductor device may have a second peak of hydrogen or helium chemical concentration located on the upper side of the semiconductor substrate. The flat portion may be located on the lower side of the semiconductor substrate relative to the second peak. The hydrogen contribution rate, which indicates the proportion of the hydrogen chemical concentration that contributes to the generation of hydrogen donors, may be 0.001 or more and 0.3 or less. The vacancy concentration of the flat portion may be 1 × 10¹¹ /cm³ or more and 1 × 10¹⁴ / cm³ or less. The hydrogen concentration at the first peak may be higher than that at the second peak. The oxygen chemical concentration in the flat area may be 1 × 10¹⁷ atoms/ cm³ or higher. The carbon chemistry concentration in the flat area may be 1 × 10¹³ atoms/ cm³ or more and 1 × 10¹⁶ atoms/ cm³ or less. The sum of the oxygen chemical concentration in the flat region multiplied by the oxygen contribution rate and the vacancy concentration in the flat region may be used as the first value of the hydrogen donor concentration. The difference between the donor concentration in the flat region and the bulk donor concentration may be used as the second value of the hydrogen donor concentration. The ratio of the first hydrogen donor concentration to the second hydrogen donor concentration may be between 0.1 and 10. In a second embodiment of the present invention, a semiconductor device is provided comprising a semiconductor substrate having an upper and lower surface and containing oxygen. The semiconductor device may have a first peak of hydrogen chemical concentration located on the lower surface side of the semiconductor substrate. The semiconductor device may also have a flat region located on the upper surface side of the semiconductor substrate beyond the first peak, containing hydrogen donors, where the donor concentration distribution in the depth direction of the semiconductor substrate is substantially (almost) flat. The semiconductor substrate may contain bulk donors. The donor concentration in the flat region may be higher than the bulk donor concentration. The first hydrogen donor concentration may be defined as the sum of the value obtained by multiplying the oxygen chemical concentration in the flat region by the oxygen chemical concentration in the flat region (which represents the proportion of the oxygen chemical concentration contributing to the generation of hydrogen donors from the oxygen chemical concentration of the oxygen) and the vacancy concentration in the flat region. The second hydrogen donor concentration may be defined as the difference obtained by subtracting the bulk donor concentration from the donor concentration in the flat region. The ratio of the first hydrogen donor concentration to the second hydrogen donor concentration may be between 0.1 and 10. In a third aspect of the present invention, a semiconductor device is provided comprising a semiconductor substrate having an upper and lower surface and containing oxygen and carbon. The semiconductor device may have a first peak of