Structural and electrical characteristics of chemical vapor deposited W/n-Si0.83Ge0.17/Si(001) and chemical vapor deposited WSix/n-Si0.83Ge0.17/Si(001)

Structural and electrical properties of chemical vapor deposited (CVD) W/n- Si0.83Ge0.17/Si(001) and CVD-WSix/n-Si0.83Ge0.17/Si(001) were studied by st ructural, chemical, and electrical characterizations. W and WSix layers wer e deposited on n - Si0.83Ge0.17/Si(001) and n-Si(001) at the growth tempera ture T-s = 350- 550 degreesC by low-pressure chemical vapor deposition util izing WF6 and SiH4 source gases. Structural and chemical properties of CVD- W/n-Si0.83Ge0.17(001) and CVD-WSiX/n-Si0.83Ge0.17(001) interfaces were anal yzed by x-ray diffraction, transmission electron microscopy, scanning elect ron microscopy, Rutherford backscattering spectroscopy, and Auger electron spectroscopy. Interfaces of CVD-WSix/n-Si0.83Ge0.17(001) were much sharper than those of CVD-W/n-Si0.83Ge0.17(001). Interfaces of CVD-W/n-Si0.83Ge0.17 (001) are very rough presumably due to encroachment of SiGe layers caused b y etching reaction of SiGe layers by WF6. Electrical properties of the CVD- W/n-Si0.83Ge0.17(001) and CVD-WSix/n-Si0.83Ge0.17(001) Schottky diodes were characterized by the current-voltage measurements. The measured effective Schottky barrier heights (phi (Bn)) of the CVD-W/n-Si0.83Ge0.17(001) Schott ky contacts were 0.56 +/-0.01 eV as the deposition temperature, T-s, of W l ayers increases from 350 to 550 degreesC, and CVD-WSix/n-Si0.83Ge0.17(001) Schottky contacts with CVD-WSix layers grown at T-s = 350 degreesC showed t he phi (Bn) values similar to those of CVD-W/n-Si0.83Ge0.17(001). (C) 2001 American Vacuum Society.