Electrical activity is the ability for electron to travel within the material. Specific solid material molecule will have free electrons to conduct thus allow electrons to freely move within the solid thus create a flow of electron current.
Conclusion, they are mechanically similar because both create a flow of particles (ions, free electrons) that enable the flow of electrons current within …show more content…
Drive-in time: t_(drive-in)=3.7*(〖10〗^(-9) cm^2)/(1.5*〖10〗^(-13) ((cm^2)/s) )=6.8 hours
In order to form the deep low concentration-boron requires at least 6.8 hours at 1100 C. This requires a lot of time and energy for almost 7 hours continuously at 1100 C.
With the surface concentration and the Dt product, we can calculated the initial dose for this Gaussian profile as
Q=C(0,t) √(πD_t )=4*〖10〗^17 √π √(3.7*〖10〗^(-9) )=4.3*〖10〗^13 cm^(-2)
This dose can be implanted in a narrow layer close to the surface, justifying for the implicit assumption of Gaussian profile that the initial distribution is the approximation of the delta function.
On the other hand, assume a T = 950C for the pre-deposition, we will have
B solid solubility at 950C=2.5*〖10〗^20 cm^(-3)
B diffusivity is 4.2*〖10〗^(-15) ((cm^2)/s) =>Q=(2C_s)/√π √(D_t )=>t_(pre-dep)=((4.3*〖10〗^13)/(2.5*〖10〗^20 ))^2*(√π/2)^2*1/(4.2*〖10〗^(-15) )=5.5 s
When compare the delta function approximation with the drive in time we got a reasonable result with:
D_(t_predept )=2.3*〖10〗^(-14)≪D_(t_(drive-in) …show more content…
We will need a lower pre-deposition temperature in order to increase the tpredep. Or we could just simply use ion implantation to have a lower dose of dopant for the process.
Since this is a furnace means that it will always at high temperature so it would be inefficient to just using the sources at solid because it took time to sublime that solid and turn it into gaseous state for diffusion sources.
The best efficient way is to use a gaseous diffusions sources. We got 2 candidates PH3 and POCl3. PH3 has a little quirk that escaping gas cannot be extinguished and exposure to fire may cause containers to rupture. This is a high temperature furnace which we will have a fire hazard so it would not wise to use PH¬3 in this. The best candidate will be POCl3 although it is an extremely hazardous but all those hazard scenario can be mitigating by applying safety countermeasure in operating the furnace as well as installing fume hood to eliminate any leak gases.
Conclusion: using POCl3 is the best since it is already in gaseous form => high efficiency, all normal standard hazard can be mitigating by applying various safety countermeasure such as safety suit, fume hood, safety