C Plane to A Plane 4° 2inch 4inch Sapphire Wafer DSP SSP Sapphire Substrate

C Plane to A Plane 4° 2inch 4inch Sapphire Wafer DSP SSP Sapphire Substrate

Definition of Sapphire Orientation:

In crystallography, a “plane” refers to a specific crystallographic orientation — that is, a flat surface defined by the atomic arrangement in a crystal.

Sapphire (α-Al₂O₃) is a single crystal with a hexagonal (trigonal) structure.

Its internal atoms are arranged in repeating layers along specific directions (axes):

C-axis (the crystal’s main symmetry axis),

A-axis and M-axis (within the basal plane),

R-plane (angled plane).

   When you say “a plane,” it’s a general term — you could be referring to any crystallographic plane, such as C-plane, A-plane, R-plane, or M-plane — each with different atomic orientation and properties.

What “C-plane sapphire” Specifically Means?

   C-plane sapphire is a sapphire crystal cut perpendicular to the C-axis, i.e., the crystal surface corresponds to the (0001) plane.

Why choose sapphire wafers? 

ZMSH Sapphire wafers recommendation: DSP 8inch 6inch Dia200mm monocrystalline Al2O3 Sapphire Substrate Prime Wafers

    Sapphire is composed of aluminum oxide (Al₂O₃), consisting of two aluminum atoms and three oxygen atoms bonded together through strong covalent bonds. Its crystal structure is hexagonal (trigonal). The most commonly used crystal orientations (cuts) include the A-plane, C-plane, and R-plane. Because sapphire has a very wide optical transmission range—from near-ultraviolet (around 190 nm) to the mid-infrared region—it is widely used in optical components, nfrared devices, high-power laser optics, and photomask substrates. Sapphire also possesses several outstanding physical properties: high acoustic velocity, igh-temperature resistance, corrosion resistance, extreme hardness, excellent optical transparency, and a high melting point (2045 °C). However, due to its high hardness and brittleness, sapphire is a very difficult material to process, which is why it is commonly used as a substrate and protective material in optoelectronic devices.

Advantages of Sapphire Wafers:

The advantages of sapphire wafers lie in their excellent optical properties, outstanding chemical and thermal stability, high mechanical strength, and well-established processing technology.

These characteristics make sapphire an ideal choice for applications in LEDs, radio-frequency (RF) devices, and emerging display technologies. It can support high-temperature epitaxial growth while ensuring device stability, reliability, and long-term durability.

High Optical Transmittance: Sapphire substrates offer high transparency from the ultraviolet (UV) to near-infrared (NIR) spectrum, enabling efficient light transmission and reduced reflection loss — a critical advantage for LED and other light-emitting devices.

Support for Next-Generation Display Technologies:

In Micro LED and Mini LED high-resolution display technologies, sapphire’s excellent optical performance and superior patterning capability make it an ideal substrate material.

High-Temperature Resistance:

With a melting point as high as (2050^{circ}C), sapphire can easily withstand the high temperatures (above (1000^{circ}C))** required for **LED epitaxial growth.

Chemical Stability:

Sapphire is chemically inert and corrosion-resistant, maintaining stability even in acidic or alkaline environments, making it highly reliable under **harsh operating conditions.

High Hardness and Strength: With a Mohs hardness close to 9, second only to diamond, sapphire possesses exceptional mechanical strength and wear resistance. This allows it to reliably support complex epitaxial layers while remaining easy to clean and mechanically robust.

Q&A:

Q: What is the crystal orientation of a sapphire?

A: Sapphire is single-crystal aluminum oxide (Al₂O₃).It has a hexagonal (trigonal) crystal structure, belonging to the rhombohedral system, space group R-3c. Sapphire (α-Al₂O₃) is a hexagonal single crystal most commonly oriented as C-plane (0001) for optical and epitaxial applications, but A-plane, R-plane, and M-plane cuts are also used depending on the desired optical, mechanical, or lattice-matching properties.

Q: What is the orientation of a wafer?

A: The orientation of a wafer defines the crystallographic plane of its surface, such as (100) for silicon or (0001) for sapphire/SiC. It directly affects material growth, device fabrication, and mechanical behavior, and is identified by flats or notches on the wafer edge.

Q: Is a sapphire wafer transparent?

A: Sapphire wafers are transparent from ~170 nm (UV) to ~5 µm (IR),offering excellent optical clarity, high hardness, and chemical durability. With AR coatings, transparency exceeds 98%, making them ideal for optical and electronic applications where clarity and durability are both required.