Titanium nitride as electrode for MOS technology and Schottky diode: Alternative extraction method of titanium nitride work function

• Published in: Microelectronic engineering Vol. 92; pp. 86 - 90
• Main Authors: Lima, L.P.B., Diniz, J.A., Doi, I., Godoy Fo, J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01-04-2012; Elsevier
• Subjects: Applied sciences; Capacitors; Compound structure devices; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Devices; Dielectric, amorphous and glass solid devices; Diodes; Electrodes; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronics; Exact sciences and technology; Metal oxide semiconductors; Physics; Schottky diodes; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon dioxide; Silicon substrates; Surface double layers, schottky barriers, and work functions; Titanium nitride; Electrical conductivity; Voltage current curve; Transistor gate; Microelectronic fabrication; Work function; Thick film; n type semiconductor; Defect; Raman spectrometry; Raman spectrum; Voltage capacity curve; MOS technology; Annealing; Titanium nitride; MOS structure; X ray diffraction; MOS capacitor; Charge density; Crystalline material; Silicon oxides; Sintering; Capacitance; Alternative method; Schottky barrier diode; Sputter deposition; Schottky barrier
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2011.04.059

Titanium nitride (TiN) films have been used as gate electrodes in metal–oxide-semiconductor (MOS) capacitors, which were fabricated with SiO2 layer as gate dielectric, and as upper electrodes in Schottky diodes on Si substrates. The TiN layer has presented the electrical resistivity of 270μΩcm and poly crystalline structure (Ti2N and TiN phase formation), which were extracted by four probe testing, and, X-ray diffraction and Raman spectroscopy, respectively. To get both MOS and Schottky devices on the same substrate, with TiN/SiO2/Si/Al and TiN/Si/Al structures, respectively, 300nm thick TiN layer was simultaneously deposited by DC sputtering process on SiO2/Si and on Si on the same n-type substrate. The MOS capacitors and Schottky diodes were sintered in conventional furnace in forming gas at 450°C for different annealing times between 5 and 30min. These devices were electrical characterized by capacitance–voltage (C–V) and current–voltage (I–V) measurements, respectively. With both measurements from capacitors and diodes fabricated on the same substrate, the TiN work function values were extracted, resulting in values between 4.5 and 4.2eV. These values agree with results from literature. Our TiN work function extraction method presents higher accuracy, due to two different measurements were carried out to extract the same parameter, and lower defect incorporation on semiconductor surface can occur, because both devices were fabricated on the same substrate at the same conditions. Furthermore, the distortion in MOS capacitor C–V curve is reduced at 10min of sintering process, indicating that the charge density at TiN/SiO2/Si/Al structures is reduced to one level of 1010cm−2. From the I–V curves of Schottky diodes, the ideality factor between 1.0 and 1.5 was extracted. And, these excellent results, such as low charge density of 1010cm−2, the ideality factor of 1.0, and work function of 4.2eV, indicates that TiN electrodes can be used for MOS technology and Schottky diode.