A Si1-xGex sputter epitaxy method using an ultra-high-vacuum-compatible magnetron sputtering technique with all Ar and H-2 mixture working gas has been introduced. The crystallinity and strain-relaxation controllability of a Si1-xGex layer grown on n-type Si(001) by our sputter epitaxy method is well comparable to those of a Si1-xGex layer grown by a standard molecular beam epitaxy (MBE) method. In the device level evaluation by forming an electron-tunneling Si/Si1-xGex asymmetric double quantum well resonant tunneling diode (ASDQW RTD), the fabricated RTD exhibits a high peak-to-valley current ratio (PVCR) of similar to 26 with low background current, the performance of which is also close to that of our recent high PVCR ASDQW RTD fabricated by gas-source MBE. On the basis of these results, our proposed method is very promising for its application to various kinds of SiGe devices. (c) 2005 Elsevier B.V. All rights reserved.