Roland Rupp

First results on silicon carbide vapour phase epitaxy growth in a new type of vertical low pressure chemical vapour deposition reactor

In this paper a new concept for silicon carbide vapour phase epitaxy (VPE) will be presented. It is based on the rotating disk technology well known in the field of III–V epitaxy. First results will be given showing excellent structural quality of the epitaxial layers together with high growth rates up to 5 μm/h and good uniformity of layer thickness over 1 inch wafers. The CSi-ratio in the process can be varied over a wide range (0.35-2.3 at 3 μm/h) without loss of surface quality. This enables a precise control of the site competition effect and, therefore, of the incorporation of acceptor and donor impurities. Thus, non-intentionally doped p- (CSi > 1) and n-type (CSi < 0.7) epilayers with carrier concentrations considerably below 1016 cm−3 can be grown.

Silicon Carbide Cvd Approaches Industrial Needs

In this paper an overview is given on the current state of epitaxial growth of SiC with special regard to our work at SIEMENS CRD. Problems concerning impurity incorporation and ways to achieve background doping levels as low as 10 14 cm −3 are discussed as well as the influence of high speed wafer rotation on the gas flow in our reactor and related effects on uniformity in thickness and doping. Precise control of the C/Si ratio in the gas phase, which is easily achieved in the described reactor, and the use of reduced pressure lead to a good control of dopant incorporation over more than 3 orders of magnitude while maintaining smooth surface morphology even at growth rates higher than 5 μm/h. Doping variations * 10 6 V/cm at N A −N D =5 * 10 −15 cm − and an electron mobility greater than 700 cm 2 /Vs at 300 K (4H-SiC). Finally it is demonstrated that the gas composition at the end of the epitaxial growth process is an important step in order to get oxygen resistant surface properties for subsequent device processing.