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Abstract: Thin film processes for Si, SiC and GaN power devices Manufacturing of high performance IGBTs, MOSFETS and SiC power devices requires backside metallization on thin wafers which poses several challenges for semiconductor manufacturing tools in regards to both wafer handling and processing. This presentation will show details of wafer handling features for reliable handling of thin or TAIKO wafers with less than 100µm wafer thickness tolerating wafer bow of up to 4mm without any contact to the device area of the wafers. Backside metallization (BSM) requires superior stress control as well as advanced temperature management. Insitu oxide etch as well as the activation of good ohmic contact are an integral part of the BSM process. Results will show how in-situ pyrometry for monitoring and documenting wafer temperature and process stability is essential to understand the thermal behavior of the wafer throughout the process tool. GaN on Si power devices require nitride stacks with perfect structures for the production of fast switching transistors. Such stacks including the initial AlN buffer layer are typically grown by MOCVD. AlN buffer layers deposited by PVD on Si(111) are suitable to replace the MOCVD grown AlN and provide distinct advantages for the following GaN growth by MOCVD. Key parameters to be achieved are perfect crystallinity, a well matching lattice constant and very low surface roughness. Electric results from HEMT structures like electron density in the two-Dimensional Electron Gas region (2DEG) and the threshold voltage Vth will be shown. |
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