Synthesis and properties of some refractory transition metal diboride thin films

Direct current magnetron sputtered ZrB2 thin films on 4H-SiC(0001) and Si(100)

“…This has also been suggested in a study by Takeyama et al [16] as well as by Shappirio et al [17]. While it is not possible to determine whether the oxygen originates from oxides in the target material or as oxygen containing species dissolved in pores present in the sintered material, we note that several studies in the literature have been performed, using target materials with densities less than the theoretical bulk value [9,10,17].…”

“…While it is not possible to determine whether the oxygen originates from oxides in the target material or as oxygen containing species dissolved in pores present in the sintered material, we note that several studies in the literature have been performed, using target materials with densities less than the theoretical bulk value [9,10,17]. Their results indicate that a denser target material is likely to enable the deposition of films with a reduced level of contaminants.…”

“…The measured amounts being typically below 0.2 at.% for H, Ar, and N and 0.4 at.% for C and 1 at.% for O. Such contents, particularly the oxygen content, must be considered to be low in PVD films compared to the literature [10,[15][16][17][18], as the growth was carried out in a HV system and without external heating in some of the processes. The oxygen level is also low compared to thermally activated CVD films deposited at a temperature of 450 °C [11].…”

“…Results on growth of films with composition deviating, sometimes substantially, from the composition of the utilized source, as well as growth of films with a high level of contaminants have been reported [2,4,6,10,[14][15][16][17][18]. The presence of a foreign element such as oxygen during nucleation of ZrB2 is likely to cause unwanted chemical reactions between the film constituents and the contaminant.…”

Improved Schottky Contacts on n-Type 4H-SiC Using ZrB2 Deposited at High Temperatures

“…[19][20][21][22] In particular, ZrB 2 possesses a very low electrical resistivity of 4.6 lX-cm and a high melting point of about 3,220°C for the bulk material, which make it more attractive than its parent metal Zr with resistivity 42 lX-cm and melting point 1,852°C. 23,24 The refractory nature of the borides offers a very attractive advantage as contact metallization for high-temperature device applications. While refractory borides have been investigated for contact and diffusion barrier metallizations on Si and GaAs, [25][26][27][28][29] there is very little reporting on the investigation of their suitability for Schottky contacts on SiC.…”