Boron trifluoride Application

5. Ion injection source for semiconductor device manufacturing process

Boron trifluoride is used as an ion injection source in the semiconductor device manufacturing process to improve the performance of semi-heterodyne devices.

When Group V atoms are doped in a crystal of Group IV silicon atoms in the periodic table, they are able to conduct electricity because of an extra free electron in the outer electron. We call the group V impurity an N-type impurity and the atom that generates the free electron a giving body. When group III atoms are doped, in contrast to the above, a hole appears due to the absence of an electron. In this hole, neighboring electrons can jump in and can move in a sequential manner. This group III impurity is called a P-type impurity, and the atom that creates the hole is called an acceptor.

Usually, phosphorus and arsenic are used as N-type impurities, and boron is used as a P-type impurity. This impurity is called dopant, and the process of adding dopant is called dopant mass. Usually, the proportion of dopant is 106-107 silicon atoms doped with 1 impurity to form a conductive region.

Dopant doping methods are thermal diffusion method and ion implantation method. The thermal diffusion method is a method in which the silicon wafer is placed in a diffusion furnace and heated to approximately 1000°C in a gas of impurity gas, at which point the impurity atoms diffuse into the silicon crystals, thus forming a conductive zone. The usual gases used in the thermal diffusion method are ethylborane (B2H6) for the P-type and phosphine (PH3) and arsine (AsH3) for the N-type.

The ion injection method is a technique in which impurity atoms are ionized in a vacuum and then accelerated in an electric field, and the ions are then driven into the crystal. The gases used in the ion injection method are boron trichloride (BF3), phosphine, and arsine. The ion injection method is rarely affected by impurities because it has a mass analyzer installed inside to select the desired ions. In addition, the amount of ion injection can be controlled by electric field regulation, and the concentration and location of ion injection can be adjusted, so it is superior to the thermal diffusion method.

 

 

6. Metallurgy and welding

BF3 can prevent the oxidation of magnesium and its alloys in the melt casting, used as a flux when welding magnesium. It is also used as a component of steel or other metal surface boron treatment agent, also used as a lubricant for cast steel. In the arc welding of titanium, if there is BF3 involved, the weld will have a strong impact resistance.

 

7. synthesis of ethylborane

BF3 can be used to prepare borane. It reacts with alkali metal hydride to produce ethylborane. React with Grignard reagent to produce organic boron compounds.

 

8. Medical treatment

With the technological advancement in the field of medicine, new antibiotic drugs are being developed. The synthesis process of these new antibiotic drugs requires boron trifluoride gas as a catalyst.