CN103400913B - A kind of rectangular graph silicon substrate for growing six side phase GaN - Google Patents

Abstract

The invention discloses a rectangular patterned silicon substrate for growing hexagonal GaN, which includes a silicon (111) plane substrate body, and a strip-shaped isolation zone is processed on the upper surface of the silicon substrate body, and the strip-shaped isolation zones are formed by mutual Composed of vertical and horizontal isolation strips with the same vertical and width, the silicon substrate body is divided into multiple rectangular growth platforms. It is characterized in that: the bisector of any angle of the rectangular growth platform is arranged in a hexagonal manner on the silicon (111) surface The included angle of any diagonal of the regular hexagon corresponding to the atoms is in the range of 0° to 5°. The restriction on the range of the included angle ensures that the widths of the horizontal grooves and the vertical grooves formed after the growth of the hexagonal GaN are basically the same. This provides a strong guarantee for the crystal quality of the epitaxial layer and the reliability of the subsequent chip manufacturing process, and it also completely solves the problem that the uncertainty of the direction of the rectangular growth platform affects the quality of the GaN crystal and the yield of the chip in the existing rectangular patterned silicon substrate technology. , Reliability issues.

Description

A rectangular patterned silicon substrate for growing hexagonal GaN

technical field

The invention relates to epitaxial growth technology of semiconductor materials, in particular to a rectangular patterned silicon substrate for growing hexagonal GaN.

Background technique:

III/V nitride semiconductor materials represented by GaN are the third-generation semiconductor materials after silicon and gallium arsenide, and have developed rapidly in recent years. III/V nitrides include GaN, AlN, InN, InGaN and AlGaN, etc., which have a continuously variable direct bandgap of 1.9-6.2eV, covering the emission wavelength from ultraviolet to far infrared, and have excellent physical and chemical stability It has been widely used in optoelectronic devices in blue, green and ultraviolet bands, especially in blue and green light-emitting diodes.

Since GaN single crystals are difficult to obtain, GaN epitaxial growth is mostly carried out on heterogeneous substrates. In addition to the most commonly used sapphire (c-plane) substrates and 6H-SiC substrates, silicon (111) plane substrates have also attracted extensive attention in recent years. Silicon substrates have the advantages of cheap price, larger size, easy peeling, electrical conductivity, and relatively high thermal conductivity, and the processing technology and integration technology of silicon materials are quite mature, making GaN-based LEDs on silicon substrates have the potential for easy large-scale integration. Advantage. However, there is a huge lattice mismatch and thermal mismatch between Si and GaN, which will introduce huge stress during the growth process, making it very difficult to obtain high-quality GaN-based LED thin films on silicon substrates.

At present, many units in the industry have solved the problem of epitaxially growing high-quality GaN-based LED films on silicon substrates, and have launched high-level GaN-based LED products on silicon substrates. Among them, dividing the entire silicon substrate into multiple regularly arranged independent rectangular growth platforms (that is, rectangular patterned silicon substrates) is one of the current mainstream technical routes. Divided into a plurality of evenly distributed independent rectangular growth platforms with the same shape and size, the isolation zone can be raised or depressed, GaN material cannot be directly grown on the isolation zone, and the isolation zone A certain width is used to ensure that the epitaxial layer on each growth platform is not in contact with the epitaxial layer on the adjacent growth platform, thereby forming a horizontal groove and a vertical groove without GaN growth between the various growth platforms, so The groove can effectively release the huge stress introduced by the silicon substrate and the epitaxial layer due to lattice mismatch and thermal mismatch during the heteroepitaxial growth process, greatly reducing the cracks in the epitaxial layer and reducing the dislocation density. Thereby obtaining high-quality GaN-based LED thin film materials.

However, the existing rectangular patterned silicon substrate technology does not consider the influence of the boundary line of the rectangular growth platform relative to the crystal orientation of the silicon (111) plane on the epitaxial growth of hexagonal GaN on it. The surface of the rectangular growth platform is a silicon (111) plane, if the crystal orientation of its boundary line relative to the silicon (111) plane is unreasonably designed, it will lead to the formation of the horizontal and vertical grooves during the GaN growth process The width of the groove is different, the stress of the epitaxial layer is unbalanced, cracks grow, the dislocation density increases, and the crystal quality decreases, which will also have a greater adverse effect on the yield and reliability of the subsequent chip manufacturing process. The above problem arises because the crystal orientation of the boundary line relative to the silicon (111) plane determines the atomic arrangement along the boundary line, and the lateral growth rate of hexagonal GaN along the boundary line depends on the atomic arrangement along the boundary line . The growth plane of hexagonal GaN is the (0001) plane, which is arranged in a regular hexagon like the atoms on the (111) plane of silicon. The growth rate of GaN is faster along the corners of the regular hexagon, and slower along the sides of the regular hexagon. . The rectangular growth platform has four boundary lines parallel to each other, wherein adjacent boundary lines are perpendicular to each other, corresponding to mutually perpendicular crystal directions. If the crystal orientation design of the adjacent boundary lines relative to the silicon (111) plane is unreasonable, the arrangement of atoms along the adjacent boundary lines will be quite different, resulting in the lateral growth rate of GaN along the adjacent boundary lines being Different, the side with fast growth rate forms narrower grooves, and the side with slower growth rate forms wider grooves.

Invention content:

The purpose of the present invention is to provide a rectangular patterned silicon substrate for growing hexagonal phase GaN, which can make the widths of the vertical grooves and the horizontal grooves substantially consistent, thereby improving the crystal quality of the epitaxial layer and the reliability of the subsequent chip manufacturing process. It provides a strong guarantee for the stability, and also completely solves the problem that the uncertainty of the direction of the rectangular growth platform affects the quality of GaN crystals, chip yield, and reliability in the existing rectangular patterned silicon substrate technology.

The purpose of the present invention is achieved like this:

A rectangular patterned silicon substrate for growing hexagonal GaN, including a silicon (111) plane substrate body, and strip-shaped isolation is processed on the upper surface (silicon (111) plane) of the silicon (111) plane substrate body Strips, strip-shaped isolation strips are composed of longitudinal isolation strips and horizontal isolation strips that are perpendicular to each other and have the same width. The strip-shaped isolation strips divide the upper surface of the silicon substrate body into multiple rectangular growth platforms. It is characterized in that:

The included angle between any angle bisector of the rectangular growth platform and any diagonal line of a regular hexagon corresponding to the hexagonally arranged atoms on the surface, ie, the silicon (111) surface, is within the range of 0° to 5°.

The industry usually adopts the (110) plane as the main reference plane of the silicon (111) plane substrate, and the main flat side is at the position <1-10>, then the above geometric relationship can be described as: any boundary line of the rectangular growth platform and the main plane The included angle of the flat sides is one of 10-20°, 40-50° or 70-80°.

The side length of the rectangular growth platform is in the range of 0.1 mm to 5 mm.

The width of the strip isolation zone is greater than 2um.

Since GaN cannot be grown directly on the strip-shaped isolation zone, a trench without GaN growth will be formed at the strip-shaped isolation zone with the growth of GaN, but because GaN has a certain lateral growth rate, the width of the trench is usually less than The width of the strip divider. Corresponding to the vertical isolation zone and the horizontal isolation zone, the grooves are also divided into vertical grooves and horizontal grooves.

The present invention limits the range of the included angle between the diagonal of the rectangular growth platform and any diagonal of a regular hexagon corresponding to the hexagonally arranged atoms on its surface, that is, the silicon (111) surface, or limits any of the rectangular growth platforms. The angle range between the boundary line and the main flat side <1-10> determines the relative crystal orientation between the boundary line of the rectangular growth platform and the silicon (111) plane substrate, that is, the boundary line of the rectangular growth platform and the Si (111) plane The positional relationship of the atomic arrangement on the upper surface can ensure that the atomic arrangement near the two adjacent boundary lines along the rectangular growth platform is basically the same, so that the lateral growth rate of GaN along the adjacent boundary lines is basically the same, so the vertical trench can be made The width of the horizontal groove is basically the same, which provides a strong guarantee for the crystal quality of the epitaxial layer and the reliability of the subsequent chip manufacturing process, and also completely solves the problem of the inconsistency of the direction of the rectangular growth platform in the existing rectangular patterned silicon substrate technology. Deterministic issues that affect the quality of GaN crystals and chip yield and reliability.

Description of drawings:

Fig. 1 is a schematic top view of a rectangular patterned silicon substrate of the present invention;

Fig. 2 is a schematic diagram of the relative positional relationship between the boundary line of the rectangular growth platform and the atomic arrangement structure on the silicon (111) surface of the present invention.

Fig. 3 is a schematic top view after growing a hexagonal GaN thin film on the substrate provided by the present invention.

detailed description:

The method of the present invention will be further described below in conjunction with the embodiments and with reference to the accompanying drawings.

A rectangular patterned silicon substrate for growing hexagonal GaN, including a silicon substrate body 1, and a strip-shaped isolation zone is processed on the upper surface (silicon (111) surface) 5 of the substrate body 1 on the silicon (111) surface 2. The strip isolation strip 2 is composed of vertical isolation strips 3 and horizontal isolation strips 4 that are perpendicular to each other and have the same width. The strip isolation strip 2 divides the upper surface of the silicon (111) substrate body 1 into multiple rectangles The growth platform 5, the included angle α between any angle bisector of the rectangular growth platform 5 and any diagonal line of a regular hexagon corresponding to the hexagonally arranged atoms on the silicon (111) surface is 0-5°.

The included angle α between any boundary line of the rectangular growth platform 5 and the main flat side <1-10> 6 is one of 10-20°, 40-50° or 70-80°.

The side length m of the rectangular growth platform 5 is 0.1mm-5mm.

The width d of the strip isolation zone 2 is larger than 2um.

Since GaN cannot be directly grown on the strip isolation zone, as GaN grows, a trench without GaN growth will be formed at the strip isolation zone 2, but because GaN has a certain lateral growth rate, the width of the trench is generally less than the width of the strip barrier. Corresponding to the vertical isolation zone 3 and the horizontal isolation zone 4 , the groove is also divided into a vertical groove 7 and a horizontal groove 8 .

When the angle α between any angle bisector of the rectangular growth platform 5 and any diagonal line of the regular hexagon corresponding to the hexagonally arranged atoms on the silicon (111) surface is 0-5°, the longitudinal groove formed after GaN growth The widths of the groove 7 and the lateral groove 8 are basically the same. This provides a strong guarantee for the crystal quality of the epitaxial layer and the reliability of the subsequent chip manufacturing process. It also completely solves the problem that the uncertainty of the direction of the rectangular growth platform affects the quality of the GaN crystal and the yield of the chip in the existing rectangular patterned silicon substrate technology. , Reliability issues.

Claims (2)

1. one kind for growing the rectangular graph silicon substrate of six side phase GaN, comprise silicon (111) face substrate bulk, strip isolation strip is processed with at the upper surface (silicon (111) face) of silicon (111) face substrate bulk, strip isolation strip is by mutually vertical, the vertical isolation strip that width is identical and horizontal isolation strip are formed, the upper surface of silicon substrate body has been divided into multiple rectangle growth platform by strip isolation strip, it is characterized in that: the angle α of the flat limit <1-10> of master of arbitrary boundary line of rectangle growth platform and silicon (111) face substrate bulk is 10 ~ 20 °, any one in 40 ~ 50 ° or 70 ~ 80 °.

2. rectangular graph silicon substrate according to claim 1, is characterized in that: the length of side of rectangle growth platform is 0.1mm ~ 5mm.