Thin film measurement accuracy and crystal life are a function of Sensor Crystal Quality. To assure that each crystal is optimised for maximum process yields and minimum downtime 100% inspection is employed. Every crystal is inspected from the Quartz Blank stage, right through to the last coating process and final frequency selection.
Certificate of Conformity
The strict Quality Control with traceable batch number records ensures that each package of crystals can be covered by a Certificate of Conformity.
Our standard crystals are 0.55 inches or 0.49 inches in diameter and have electrodes configured with a gold or silver film deposited onto a special adhesion layer. The crystal blank contour is plano-convex for smooth frequency response over the crystal life and the crystal orientation is AT-cut for good frequency stability with temperature. These crystals will work very successfully with most thin film monitors and controllers.
Special Frequency Bands
Some multi-layer and other specialised thin film applications can be better served by the use of crystals which arc tuned to a very narrow frequency band. Similarly, certain controllers are also designed to operate with crystals of a selected frequency band. Testbourne will help users to select the correct crystal for their thin film controller or application.
Testbourne can supply the blank non-coated 5 MHz and 6 MHz crystals when requested. These can be a viable option for some crystal users.
Gold or Silver Coated?
Silver coated crystals may give longer life than gold coated crystals. Tests in an ion plating system where TiN and Al were deposited, showed a 50% longer life for the silver coated crystals. They have also performed well in DC and RF sputtering systems. However, silver coated crystals react to moisture, fluorides and sulphides for example. It may be worth testing the two types of crystals when commencing new thin film processes.
Custom "On - Hold" Service
As a specialised component and materials supplier, we provide a custom "On-Hold" service to support many laboratories and manufacturing companies. Our customer support department monitors customers' schedules and maintains back-up stocks of standard and non-standard crystals for each contacted user.
Crystal failures are quite often caused by-worn or damaged sensor heads, cables and accessories. We have a range of sensor heads and other components available to support our ex-stock crystal service. Data sheets are available detailing each item.
Maxtek's 1" Sensor Crystals include our unique wrap-around electrode design so that both electrode connections are made on the sealed side of the crystal allowing for use in conductive liquids. Use these crystals with any Maxtek crystal holder or cell for a rugged, easy to use and stable housing for QCM experiments in both liquid and gas phase.
The crystals are offered in either a low cost unpolished finish or a highly polished finish to reduce errors due to liquid trapping. Maxtek also offers AT cut crystals optimized for either 25oC or 90oC to minimize measurement errors due to temperature. Various electrode materials are available. Please contact us for any special crystal requirements.