You are asked to determine the concentration of a diffusing gas at a given depth on a metal surface after a given time. If you know the temperature of the metal, the surface concentration of the gas, and the diffusion coefficient, describe how you would approach this problem.

Aluminum atoms are to be diffused into a silicon wafer using both predeposition and drive-in heat treatments; the background concentration of Al in this silicon material is known to be 3.5 × 101⁹ atoms/m³. The drive-in diffusion treatment is to be carried out at 1050°C for a period of 4.0 h, which gives a junction depth x; of 3.0 µm. Compute the predeposition diffusion time at 950°C if the surface concentration is maintained at a constant level of 2 x 1025 atoms/m³. For the diffusion of Al in Si, values of Qd and Do are 3.41 eV and 1.38 × 10-4 m²/s, respectively.

I am trying to calculate surface concentration: gamma = -(1/RT)(dy/d(ln(C)) and express in units of mol/m^2. However I cannot seem to get the units right. I am unsure which R gas constant units to use. I need to convert the (dy/d(ln(C)) units: (dyn/cm)(mol/L) into terms of mol/m^2. And the same for the R gas constant units.

DON'T COPY CHEGG. I NEED A NEW ANSWER!!!

Calculate the capillary effect in mm in a glass tube of 2mm diameter, when immersed in (1)water, (2)mercury. The temperature of the liquid is 25°C and the values of surface tensions of water and mercury at 25°C in contact with air is 0.0755 and 0.59N/m respectively. The angle of contact for water is 0° and 130° for mercury . Take the density of water 1000 kg/m3, specific gravity of mercury is 13.6. The capillary effect of water in mm is equal to= The capillary effect of mercury in mm is equal to=

A thermal evaporator is used to deposit aluminum. The aluminum charge is maintained at a uniform temperature of 1100 o C. If the the vapor pressure of aluminum is about 1x10-3 torr at that temperature, calculate the evaporation rate of aluminum?

The diffusion coefficient of Ni in Cu at 1025 C is 10-9 cm2 s-1. How long does it take for the mean square root of the distance to be 1 cm?

Thermal fluid mechanics Detailed solution With an understanding of the laws of the subject

True or False? Justify your answer. A. In a rectangular drug delivery device that consists of a drug reservoir and a diffusion barrier made of a polymer gel, the steady state diffusion (mass transfer) rate through a barrier of thickness 1 cm was found to be 20 mg/day. If the barrier thickness were to be doubled keeping the reservoir drug concentration the same, the mass transfer rate would be 10 mg/day. B. In a spherical drug delivery device consisting of a core reservoir surrounded by a polymer gel barrier, the steady state diffusion (mass transfer) rate through a barrier of thickness 1 cm was found to be 20 mg/day. If the barrier thickness were to be doubled keeping the reservoir drug concentration the same, the mass transfer rate would be 10 mg/day.

A thin plastic membrane is used to separate helium from a current.gaseous. Under steady-state conditions, a concentration of helium in the membrane is known to be 0.02 and 0.005 kmol/m³ on the inner and outer surfaces, respectively. If the membrane has a thickness of 1 mm and the coefficient ofbinary diffusion of helium to plastic is 10^(-9) m²/ s, what is the value of the flow diffusive?