Laytec - in-situ Monitoring Sensors for Thin-Film Applications

Founded in October 1999, LayTec quickly became a market leader in compound semiconductor process monitoring instrumentation, especially for LED production. During MOVCD and MBE the LayTec metrology gives direct access to all key epitaxial growth properties with extreme precision! Thereby LayTec’s metrology became a key enabling factor for new technologies and devices, specifically in the ongoing Solid-State-Lighting revolution.

Since 2009 a further class of LayTec products is on the market: advanced in-line metrology, especially designed and optimized for large-area deposition techniques such as amorphous, polycrystalline, and organic thin-films.

The ability to control your deposition process in real-time offers high benefits: anomalies are quickly identified and corrected, development cycles are accelerated, transfer and ramp-up of established processes to new lines are facilitated and conditions are easily re-established after maintenance. This all adds up to greater yields and reduced costs.

* Pyro 400 provides access to the true wafer surface temperature of GaN specifically for infra-red transparent substrates (Sapphire, SiC), where the infra-red pyrometry measures the substrate surface temperature only.

EpiTT and EpiTwin TT – The Family of Metrology Tools for LED Production

These metrology systems have been specifically designed as a production tool for maximizing wafer yields in Nitride-based LED and laser production processes. They feature emissivity-corrected temperature measurement based on the combination of a pyrometry and a reflectance measurement. A second reflectance wavelength is used for simultaneous growth rate measurements. The included software offers wafer and area selective measurements and additional analysis options. EpiTT is adaptable to every thin-film deposition chamber which has optical access to the wafer surface. EpiTwin TT has two optical heads for measurements at two independent positions in double-ring production reactor configurations. EpiTriple TT and EpiQuatro TT offer three or four optical heads for even larger systems using three or four rings of wafers.

Pyro 400 – In-Situ Pyrometer for Direct GaN Surface Temperature Measurements

Until now, researchers and operators have had to suffice with susceptor temperature detection below the sapphire or SiC wafers, often called the pocket temperature, using conventional infrared pyrometry. At infrared wavelengths the wafers and layers are transparent, thus their surface temperature is not measurable. Bowing effects of large wafers cause dramatic temperature deviations across the diameter of the wafer. Temperature decreases in direct relation to the increase in distance between pocket and wafer. The larger the wafer, the greater the local deviation between wafer surface temperature and pocket temperature.

With a conventional infrared promoter, these deviations remain undetected. directly measures the surface temperature of the GaN layers at high precision by detecting 400 nm light. Data gathered across the entire diameter of the wafer creates a complete profile of surface temperature variation arising from bowing effects. These temperature differences are the cause of inhomogeneities in the active layer structures. Simply put, the Pyro 400 gives you the necessary insight to regulate temperature across the wafer surface and maximize your yields.

EpiCurve® TT Family for Wafer Bowing, Temperature and Growth Rate Control

The EpiCurve®TT provides all the parameters necessary to optimize yield and minimize bowing-related inhomogeneities in GaN LED production, GaAs/Ge-based solar cells, quarternary materials and many other applications. It includes all features of EpiTT and, additionally, measures wafer bow, film composition, surface morphology, and other parameters. Advanced tools provide monitoring of aspherical bow in 2 orthogonal directions measurements on double-sided polished and patterned substrates (EpiCurve®TT AR). Multi-head configurations the EpiCurve®Twin TT and EpiCurve®Triple TT are specifically designed for use with multiple ring reactors. Separate compact optical EpiTT heads take individual temperature and reflectance measurements on each ring.