Si1 − xGex sputter epitaxy technique and its application to RTD

A Si1 − xGex sputter epitaxy method using an ultra-high-vacuum-compatible magnetron sputtering technique with an Ar and H2 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 ∼ 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.