Equipment Description
The electron beam (E-beam) evaporator is used to coat samples with various metals. A high-intensity beam of electrons is focused on the center of a crucible containing the material to be evaporated. The energy from the electron beam melts a region of the source metal. Material evaporates from the source and covers the sample with a thin layer. Unlike sputtered films, evaporators only coat the surface facing away from the substrate. E-beam evaporators will provide very little coating to the sides of any features that are perpendicular to the surface of the substrate. In a typical process, the chamber is pumped down to a pressure of 5e-7 Torr to increase the mean free path. The mean free path of a gas molecule is the average distance the molecule travels before it collides with another molecule. This prevents air molecules from interrupting metal atoms as they travel from the evaporation source to the substrate. Then, the metal is heated to the point of vaporization by a high-intensity beam of electrons. This causes the metal to evaporate, and the metal molecules travel in a straight line to be deposited on the substrate. Typical deposition rates range from two to five angstroms per second.
| Institute |
Georgia Tech |
| Department |
IEN - Micro/Nano Fabrication Facility |
Sub Tool Of  |
Marcus Inorganic Cleanroom |
| |
Capable of evaporating: SiO2, Si, TiO2, Al203, Hf02, ITO
Manufacturer: CHA Industries
Model Number: Mark 40
Room Number: 1279
Radiation Safety Required: Yes
System Components and Data
System Components: Ion gauge, valve controller, IC5/Deposition controller, crucible selector, power supply controller, XY sweep, shutter and hoist control
Miscellaneous: The E-beam system holds six separate evaporation sources, allowing for evaporation of multiple materials in a single run. It has the capability to process a variety of sample sizes ranging from less than 1 cm2 to 4" wafers. It uses a cryo-pump for rapid pump down. Electron beam power is automatically controlled for uniform evaporation with little operator work. The E-beam system can process up to 20 3" (or less) samples simultaneously using a multiple-sample dome wafer holder.
Metallization Calibration Data: (Updated Jan 2020)
| |
Z-Ratio |
Tooling Factor |
| SiO2 |
1.000 |
327.2 |
| TiO2 |
0.409 |
200.0 |
| Si |
0.712 |
300.0 |
| Al2O3 |
0.336 |
279.0 |