Epitaxial sheet (EPI) and its application

Epitaxial sheet (EPI) and its application

Epitaxial sheet (EPI) refers to the semiconductor film grown on the substrate, which is mainly composed of P-type, quantum well and N-type. Now the mainstream epitaxial material is gallium nitride (GaN), and the substrate material is mainly sapphire. Silicon, carbonization in three, quantum Wells generally for 5 commonly used production process for metal-organic gas phase epitaxy (MOCVD), which is the core part of the LED industry, the need for higher technology and larger capital investment.

At present, it can be done on the silicon substrate ordinary epitaxial layer, multi-layer structure epitaxial layer, ultra-high resistance epitaxial layer, ultra-thick epitaxial layer, the epitaxial layer resistivity can reach more than 1000 ohms, and the conductive type is: P/P++, N/N+, N/N+, N/P/P, P/N/N /N+ and many other types.

Silicon epitaxial wafers are the core material used to manufacture a wide range of semiconductor devices, with applications in consumer, industrial, military and space electronics.

Some of the most important microelectronics applications employ multiple production-proven and industry-standard silicon epitaxy process technologies:

Diode

• Schottky diode

• Ultra-fast diodes

• Zener diode

• PIN diode

• Transient Voltage Suppressor (TVS)

• and others

Transistor

• Power IGBT

• Power DMO

• MOSFET

• Medium power

• Small signal

• and others

Integrated circuit/Bipolar integrated circuit

• EEPROM

• Amplifier

• Microprocessor

• Microcontroller

• Radio frequency identification

• and others

The epitaxial selectivity is generally achieved by adjusting the relative rate of epitaxial deposition and in situ etching. The gas used is generally the chlorine-containing (Cl) silicon source gas DCS, and the selectivity of epitaxial growth is realized by the adsorption of Cl atoms on the silicon surface in the reaction is smaller than that of oxides or nitrides. Since SiH4 does not contain Cl atoms and has low activation energy, it is generally only used in low temperature total epitaxy process. Another commonly used silicon source, TCS, has low vapor pressure and is liquid at room temperature, which needs to be imported into the reaction chamber through H2 bubblers, but the price is relatively cheap, and its rapid growth rate (up to 5 um/min) is often used to grow relatively thick silicon epitaxial layers, which has been widely used in the production of silicon epitaxial sheets. Among Group IV elements, the lattice constant of Ge (5.646A) differs least from that of Si (5.431A), which makes the SiGe and Si processes easy to integrate. The SiGe single crystal layer formed by Ge in single crystal Si can reduce the band gap width and increase the characteristic cut-off frequency (fT), which makes it widely used in wireless and optical communication high frequency devices. In addition, in advanced CMOS integrated circuit processes, lattice stress introduced by the lattice constant mismatch (4%) of Ge and Si will be used to improve the mobility of electrons or holes, so as to increase the operating saturation current and response speed of the device, which is becoming a hot spot in semiconductor integrated circuit technology research in various countries.

  Due to the poor electrical conductivity of intrinsic silicon, its resistivity is generally more than 200ohm-cm, and it is usually necessary to incorporate impurity gas (dopant) in the epitaxial growth to meet certain electrical properties of the device. Impurity gases can be divided into two types: N type impurity gases commonly used include phosphoane (PH3) and arsenane (AsH3), while P type is mainly borane (B2H6).