High-quality quartz crystal manufacturers

The stability and longevity of a crystal affect not only the accuracy of rate and thickness measurements, but more importantly the successful completion of the process being controlled. Thanks to strict manufacturing process, SungThai crystals ensure high quality and durability. It allows for reliable quality control and lower price than the quartz crystals of well-known brands with same quality. SungThai’s 6 MHz and 5 MHz crystals are available in gold, silver, or alloy electrodes and come in a variety of packages depending on your needs. These crystals can be used in various evaporation monitors (e.g. INFICON, Balzers, Ulvac, MAXTEC). 6 MHz and 5 MHz crystals are offered with gold or silver electrode and in 10-unit package.

Choose & cut crystals

Thin film measurement accuracy and crystal life are a function of sensor crystal quality.We assure that each crystal is optimized for maximum process yields, and use first-class quartz bars with long growth cycle and high Q value as the raw materials. Every crystal is inspected from the quartz blank stage, right through to the last coating process and final frequency selection. 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.

Choose & cut crystals SungThai


The piezoelectric quartz wafer is placed on the rotary grinder for preliminary grinding. The quartz wafer after the rotary grinding needs to be further ground with the grinding machine.

Grind the surface of quartz crystals and allow its thickness and roughness to meet the requirements. Generally, actual crystal thickness is smaller than theoretical thickness because subsequent vacuum evaporation step will apply a metal film on crystal surface resulting in increase of crystal thickness. It can be expressed with following formula: theoretical thickness = actual thickness + coating thickness.

Soaking & Etching

Place ground quartz crystal in a container and soak it with a solution to remove grits on its surface and whiten it.

Then etch quartz crystal with a solution to remove protective film on its surface and provide the quality for subsequent vacuum coating.

Frequency sorting

Depending on customers’ need on products, screen and sort quartz crystals with a frequency sorter.

Cleaning quartz crystals

Chemical cleaning

Perform chemical cleaning on quartz crystals to remove foreign matters on the surface of quartz crystals. 28 kHz + 40 kHz ultrasonic cleaning and acidic cleaning to remove metal ions and oily matters to ensure cleanliness of crystals.


Semi-finished products are clamped by automatic loading machine and conveyed to vacuum coating machine.

Coated Quartz

Apply metal film of certain thickness on cleaned quartz crystals by using magnetron sputtering technique and allow the crystal frequency to meet the requirements in the design. Driven by electric field, electrons accelerate and fly towards quartz crystal; in this process, electrons collide with argon ions, generating large amount of argon ions and electrons. Driven by electric field, argon ions accelerate and bombard the target, ejecting large amount of target atoms; neutral target atoms or molecules deposit on the crystal to form film. It has advantages of good controllability and repeatability of film thickness (successful coating in one run), strong adhesion between film and quartz crystal (target particles have higher energy than evaporation process by 1 order of magnitude) and high efficiency; it can manufacture thin film of various materials.

coated quartz(Magnetron sputtering machine)


Refine crystal grains and condition the texture to eliminate textural defects and achieve more stable frequency.


100% test and inspection

To maximize service life of crystals and achieve stable and accurate control on deposition rate, each crystal undergoes following tests:
1. Impedance – Impedance test helps assure stability of measurement and service life of crystals. Impedance parameter indicates electrical contact of crystal and adhesion of electrode.
2. Frequency – Assure that initial frequency is within small range; it helps assure accurate thickness measurement.
3. Visual inspection – Each crystal is inspected for electrode uniformity, surface flaws and other imperfections so as to eliminate poor adhesion of electrode and possible contamination.

Testing system


Acceptable products are packaged and stored. Vacuum packaging avoids impact of outside moisture and dust on the products, ensures key parameters of crystals and maximizes quality stability of crystals.

Vacuum sealing machine

Custom “On-Hold” Service

As a specialized 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 quartz crystals for each contacted user.

Special Frequency Bands

Some multi-layer and other specialized 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. SungThai will help users to select the correct quartz crystals for their thin film controller or application.

Main equipment for manufacturing

Rounding machine, grinding machine, ultrasonic washing machine, water purifying machine, magnetron sputtering coating machine, annealing oven, frequency sorter, terminal tester, automatic loading machine, crystal etching machine, CNC lathe, vacuum sealing machine, air compressor, crystal angle sorter, cooling tower, Class 1,000 clean room with secondary cleaning

Main materials for manufacturing

Ammonium hydrogen fluoride, grinding fluid, gold, silver, aluminum, argon


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  • Developer of Chinese industrial standard for crystals.

  • OEM/ODM manufacturing of crystal components for nearly 60 years