Formation of device-grade epitaxial silicon films at extremely low temperatures by low-energy bias sputtering

Device‐grade epitaxial single silicon layers have been formed at extremely low temperatures of about 300 °C by low‐energy bias sputtering in conjunction with in situ substrate surface cleaning and an ultraclean processing environment. Dopant impurities in the target material are fully incorporated into the sputter‐deposited silicon film and these impurities are 100% electrically activated without any additional heat cycles. An epitaxial silicon film having a resistivity as low as 0.0014 Ω cm has been obtained using a heavily arsenic‐doped silicon block as a target material. A p‐n junction diode formed by directly depositing a phosphorus‐doped n‐type epilayer on a p‐type substrate indicates a reverse current level as low as 1.88×10−9 A/cm2 at a reverse bias voltage of 5 V, thus verifying that the in situ substrate surface cleaning by low‐energy Ar ion bombardment is very effective and damage free. The electrical characteristics of a grown film have shown a good correlation to the crystal structure of the f...