Characterizations of Hf_xMo_yN_z Alloys as Gate Electrodes for n- and p-Channel Metal Oxide Semiconductor Field Effect Transistors

Abstract

In this article, the work functions (È m ) of hafnium-molybdenum (Hf x Mo y ) alloys were modified using nitrogen in dc reactive cosputtering for the first time. The Hf x Mo y N z alloys show low resistivity and excellent thermal stability up to 900 C. In addition, the work functions (È m ) of the Hf x Mo y N z alloys were tuned from the conduction band (4.17 eV) to the valence band (5.16 eV) by increasing the nitrogen flow ratio. From the X-ray diffraction (XRD) data, the MoN(200) peak can be observed for samples with a nitrogen ratio higher than 6%, which was responsible for the work function (È m ) increase in the Hf x Mo y N z alloys.

Threshold Voltage Tunability of p-Channel Metal Oxide Semiconductor Field-Effect Transistor with Ternary HfxMoyNz Metal Gate and Gd2O3 High-k Gate Dielectric

“…The metal m can be affected by factors such as stress, defects, and crystalline orientation. From a previous work, 5) we believe that the mechanism of the modulation of m involves crystalline orientation. Hf x Mo y N z /Gd 2 O 3 pMOSFET devices with N 2 flow ratios of 0, 6, and 10% have been demonstrated.…”

“…For ultrathin-body silicon-on-insulator (UTB-SOI) devices, the gate-to-channel controllability is enhanced so that the required m values for an n-channel device have been increased to 4.4 -4.6 eV and those for a p-channel device have been decreased to 4.8 -5 eV. Several m modulation techniques have been investigated such as the use of nitrogen concentration control, 5,6) a fully silicided gate, 7) a laminated structure, 8) metal intermixing, 9) and metal alloy. 10,11) The nitrogen concentration controlled method is a simple and cost-effective technique for metal gate m modulation.…”

Threshold Voltage (V_th) Tunability of pMOSFETs with Ternary Hf_xMo_yN_z Metal Gate and Gd₂O₃ High-k Gate Dielectric

“…The metal work function can be affected by stress, defects, crystalline orientation, and so on. From pervious work[4], we believe that the mechanism of the modulation in work function was speculated by crystalline orientation. The Hf x Mo y N z /Gd 2 O 3 pMOSFET device with N 2 flow ratio of 0, 6, and 10% has been demonstrated.Figure 7 shows the typical transfer characteristic(I ds -V gs ) of Hf x Mo y N z /Gd 2 O 3 pMOSFET with N 2 flow ratio of 0, 6, and 10%.…”

Negative Bias Temperature Instability of p-Channel Metal Oxide Semiconductor Field Effect Transistor with Novel HfxMoyNz Metal Gate Electrodes

“…Several work function modulation techniques have been investigated, such as implanted metals, 1) fully silicided gates, 2) and metal alloys. 3,5) In previous work, 6) the effects of nitrogen flow ratio on the work function (È m ) of Hf x Mo y N z metal gates have been demonstrated. The work function (È m ) of Hf x Mo y N z can be tuned from the silicon conduction band (4.17 eV) to the valence band (5.16 eV) by increasing the nitrogen flow ratio.…”