Lu F.-LLiu Y.-CTsai C.-EYe H.-YCHEE-WEE LIU2021-09-022021-09-02202007431562https://www.scopus.com/inward/record.uri?eid=2-s2.0-85098229436&doi=10.1109%2fVLSITechnology18217.2020.9265009&partnerID=40&md5=6e6462c249f2c4c6813cfec0eabc3aa3https://scholars.lib.ntu.edu.tw/handle/123456789/580639The record low contact resistivity (pc) of Ti contact to Ge:B (8.1*10-10Omega-cm-2) is achieved by in-situ doped CVD using the high-order Ge precursor (Ge2H6). The best achievable [B]. of 7*1020cm-3} and extended epitaxial process window are obtained using Ge2H6. By optimizing the [B] and [Sn], 2% Sn addition into Ge epitaxy reaches the lowest (pc) of 4.1*10-10 Omega-cm-2. Further Sn addition (4.7% and 13.2%) increases pc due to reduced [B], and degrades the thermal stability. The record low resistivity (2*10-4Omega-cm) among epitaxial p-type Ge and GeSn is also demonstrated. Optimized metal etching processes (Cl2+BCl3 for metal on GeSn:B, while C12 for metal on Ge:B) are necessary to minimize etching of GeSn:B and Ge:B, and to fabricate the test structure. A two-sheet-resistance model is used to correctly extract the pc. B segregation (> 1*1021cm3) at the metal/semiconductor interface enables the record low pc. ? 2020 IEEE.Etching; Germanium; Segregation (metallography); Semiconductor alloys; Tin; VLSI circuits; B segregation; Contact resistivities; Epitaxial process; High-order; Low resistivity; Metal etching; Test structure; Ti contacts; Tin alloysconference paper10.1109/VLSITechnology18217.2020.92650092-s2.0-85098229436