P-type Doping of Silicon Suitable for Structures with High Aspect Ratios by Using a Dopant Source of Boron Oxide Grown by Atomic Layer Deposition

• Main Authors: Kalkofen, Bodo, Mothukuru, Venu Madhav, Lisker, Marco, Burte, Edmund P.
• Format: Conference Proceeding
• Language: English
• ISSN: 1938-5862; 1938-6737
• DOI: 10.1149/1.3700939

For the first time successful application of thin boron oxide films grown by atomic layer deposition (ALD) as dopant source for shallow silicon doping is presented. ALD of B2O3 was carried out using tris(dimethylamido)borane and ozone as precursors. A growth per cycle of 0.3 Aå was obtained for 50 °C deposition temperature. Pure B2O3 films were highly instable after exposure to air but could be protected by thin Sb2O5 films that were in-situ grown by ALD as well. Rapid thermal annealing resulted in high concentration of active boron close to the silicon surface. The dependence of the doping results on the thickness of the initial B2O3 films could be shown and the favourable capping properties of the Sb2O5 material, which is chemically very stable in the as-deposited state but volatile and hence self-destructive at the annealing temperatures, were demonstrated.