Mo/Ni and Ni/Ta–W–N/Ni thin-film contact layers for (Bi,Sb)2Te3-based intermediate-temperature thermoelectric elements

XVII Interstate Conference Thermoelectrics and Their Applications --- 2021" (ISCTA 2021 St. Petersburg, September 13-16, 2021 Obtaining and investigation of ohmic contacts with high adhesion to thermoelements

“…When forming contact systems in thermoelements, as a rule, the adhesive strength and transient contact resistance are determined by the contact layer formed directly on the surface of TE material. This is confirmed by a number of, including our works [6,11,12]. Ni has proven itself well as a contact material up to temperatures of 500 K [3,6,11,41,42].…”

“…This can be accompanied by the formation of solid solutions or intermetallic compounds at contact interface, which have a lower value of electrical conductivity and mechanical strength. Therefore, in a number of cases, it is necessary to organize a diffusion barrier between the substrate and the deposited contact layer [6,11,13,14,[30][31][32].…”

“…In addition, in thermoelements with multisection legs, the sections are commutated using contacts. It is advisable to use multisection legs in thermoelements with a wide range of operating temperatures [6][7][8][9][10][11]. In such a thermoelement, each section of leg operates in certain temperature range and is made of various thermoelectric materials having the maximum thermoelectric figure of merit at these temperatures.…”

“…In simple thermoelements operating at low temperatures, contacts are usually made of one or two contact layers of metals, for example Ni or Ni/Au. In multisection thermoelements operating at wide temperature range, it is necessary to create contact multilayer systems [11][12][13][14], for example Ni/(Ta−W−N)/Ni or Mo/(Ta−W−N)/Ni [6].…”

“…There are several methods for the formation of contact layers in thermoelements. It is promising to obtain them by the method of vacuum sputtering [6,11,[15][16][17][18][19], which provides a minimum value of contact resistance and good adhesive strength. In addition, vacuum sputtering can be used in combination with other methods, for example, chemical or electrochemical deposition of contact metal layers.…”