If oxides have to be deposited on the substrate, Reactive Sputtering is applied. In addition to the sputter gas Argon, Oxygen is introduced into the vacuum chamber. Radio Frequency Sputtering RF Sputtering allows for sputter deposition of insulating non-conductive materials. RF Sputtering works by using power delivered at radio frequencies — often fixed at On the positive cycle, electrons are attracted to the target material or surface giving it a negative bias.
On the negative cycle, ion bombardment of the target to be sputtered continues. For more information on other sputtering techniques, please click here. Many other variants of sputter techniques exist.
The interested reader is encouraged to see the diverse literature, for example at www. For each layer to be deposited reproducibly the researcher has to generate a recipe comprising all parameters of the device.
Please note that most coatings comprise many films deposited successively. The vacuum system of a sputter coater is more complex than in thermal or e-beam evaporators. Like all coaters, a base pressure in the high-vacuum range is required. This is necessary to have clean surfaces — especially on the substrate — and avoid contamination by residual gas molecules.
Usually, base pressures before initiating the coating process are 10 mbar or better. Following this, the sputter gas is introduced, which means an additional gas flow to be handled by the vacuum pump. Pressures during sputter deposition are in the mTorr range, 10 -3 to some 10 -2 mbar. The gas flow is usually adjusted by a flow controller, while the thickness of the layer is governed by a film thickness controller.
The turbomolecular pump is the classic workhorse in sputter devices. Sputtering Carbon thread evaporation Carbon rod evaporation E-beam evaporation Rather diffuse coating from all sides , influenced by the sputter vacuum Minimal heat transfer to the sample Easy to operate and set up During coating vacuum at 10—2 mbar range can be problematic for cryo applications Great variation of metals Pulsed evaporation highly controllable Easy to operate Low heat transfer to sample due to short pulses No continuous rotation while coating Fine grains Fast coating Continuous rotation Defined purity of the carbon More heat development than carbon thread Finest grains Directional coating shadowing!
Every Leica EM ACE can be configured or upgraded to a cryo coater Basic cryo set Freeze fracture cryo set Optional: Glow discharge for all instruments to make carbon coated grids hydrophilic. Interested to know more? Contact Us Do you prefer personal consulting? Leica Mikrosysteme Vertrieb GmbH. Ernst-Leitz-Strasse Routeplanner google maps. Rather diffuse coating from all sides , influenced by the sputter vacuum Minimal heat transfer to the sample Easy to operate and set up During coating vacuum at 10—2 mbar range can be problematic for cryo applications Great variation of metals.
Pulsed evaporation highly controllable Easy to operate Low heat transfer to sample due to short pulses No continuous rotation while coating.
Fine grains Fast coating Continuous rotation Defined purity of the carbon More heat development than carbon thread. Finest grains Directional coating shadowing! Biology SEM imaging. High resolution SEM analysis. For example, a silicon target reactively sputtered with oxygen gas can produce a silicon oxide film, or with nitrogen can produce a silicon nitride film which are at the heart of the semiconductor industry.
Read more…. Co-Sputtering is where two or more target materials are sputtered at once in the vacuum chamber and is often used with Reactive Magnetron Sputtering to produce thin films that are compounds such as alloys or composites.
It is widely used in the optical and architectural glass industries. By utilizing Reactive Co-Sputtering of two target materials such as Silicon and Titanium with dual Magnetron Sputtering, the refractive index or shading effect of the glass can be carefully and precisely controlled on applications ranging from large scale surfaces such as skyscraper architectural glass to sunglasses.
It is also widely used producing solar panels. DC or Direct Current Sputtering is the simplest and most frequently used with electrically conductive target materials like metals because it is easy to control and relatively low cost in power consumption.
When possible, DC Sputtering can be a relatively inexpensive, cost effective solution for coating a wide range of decorative metal coatings. Read more …. However, DC Sputtering has limitations when it comes to dielectric target materials — coatings which are non-conducting insulating materials that can take on a polarized charge.
During DC Sputtering, the gas in the vacuum chamber becomes ionized. As a result, positive ions are produced which accumulate on the surface of the target face giving it a positive charge. This dielectric buildup of a positive charge over time can terminate the discharge of sputtering atoms. RF or Radio Frequency Sputtering alternates the electrical potential of the current at radio frequencies to avoid a charge build up.
By alternating the current in this manner, each phase of the cycle has the effect of reversing the buildup when the current is only flowing continuously in one direction.
As with DC Magnetron Sputtering, RF Magnetron sputtering coaters increases the growth of the thin film by increasing the percentage of target atoms which become ionized. Pulsed DC Sputtering is where the target is bombarded with powerful voltage spikes to clean the target face and prevent the buildup of a dielectric charge. These voltage spikes which clean the target surface are usually set at frequencies ranging from 40 to KHz. The process starts by electrically charging a sputtering cathode which in turn forms a plasma causing material to be ejected from the target surface.
The target material is either bonded or clamped to the cathode and magnets are used to ensure stable and uniform erosion of the material. At a molecular level the target material is directed at the substrate through a momentum transfer process.
0コメント