Epitaxy Arsenides & Phosphides

The deposition of single-crystalline compound semiconductor layers (epitaxy) with well-defined optical and electrical properties are the basis for GaAs- and InP-based microelectronics and optoelectronics.

For microelectronics, layer structures are developed for GaAs-based power HBTs for high operating voltages. Layers for high-power laser diodes with very high beam quality are available in the wavelength range between 635 nm and 1220 nm. Using two-step growth processes, structures with gratings for wavelength stabilization are fabricated as well. In addition to these edge emitting lasers, FBH works on surface emitting lasers with electrical pumping (VCSELs) or with optical pumping for semiconductor disk lasers (SCDLs).

All these structures require a very good material quality, well-controlled interfaces and precise adjustments of composition and doping of individual semiconductor layers. The development and optimization of deposition processes for the material systems (Al,Ga)As, (Ga,In)(As,P), and (Al,Ga,In)P yielding the required high layer quality is the mission of the group. Using these processes, layer structures are supplied for internal usage as well as for external partners and customers.

The epitaxial growth technique is metal organic vapour phase epitaxy (MOVPE) using TMGa, TEGa, TMIn, TMAl, arsine, phosphine, disilane, DMZn and CBr4 as sources. An accurate control of the purity of these starting materials is essential for the high quality of FBH's layer structures.

Two MOVPE systems of the type Aixtron AIX 200/4 with 3×2" or 1×3"/4" capacity are used for exploratory work and production in small volumes. A production scale reactor AIX 2400G3 (5×4") is used for larger volumes. The systems are equipped with in-situ tools for optical growth control by reflectance and reflectance anisotropy spectroscopy (RAS). FBH extensively uses these tools and closely cooperates on the development of these techniques LayTec GmbH.

The Ferdinand-Braun-Institut also supplies customer-specific layer structures in small and medium volumes on demand. If larger volumes are required, FBH cooperates with its spin-off TESAG.