Controlling the Pd Metal Contact Polarity to Trigonal Tellurium by Atomic Hydrogen‐Removal of the Native Tellurium Oxide

Abstract

Palladium (Pd) electrodes have enabled superior performance in Te‐based devices. Theory predicts strong Fermi level (EF) pinning near the Te valence band, which likely explains the predominant p‐type conduction in Te transistors. The effects of the native TeOx on the contact polarity has not been explored. In this work, X‐ray and ultraviolet photoelectron spectra (XPS and UPS, respectively) reveal the native surface oxide de‐pins the EF between Pd and trigonal Te (t‐Te) and can reduce contact resistance of hole and electron contacts to Te for back end of line‐compatible complementary logic circuits. Atomic hydrogen reduces the native t‐Te oxide below the XPS detection limit, after which, the EF resides near the t‐Te conduction band edge. Therefore, an n‐type band alignment is formed between Pd and t‐Te via an atomic hydrogen treatment. Furthermore, UPS shows the EF is pinned near the t‐Te conduction band edge. XPS indicates the formation of a PdTex intermetallic at the Pdt‐Te interface also affects the electrostatics of the interface. The concentration of PdTex is 40% higher when TeOx is removed from the t‐Te surface before Pd metallization, likely the root cause of the low (pinned) work function when the native oxide is absent.

Etching and Compositional Ratio Effect on the Surface Properties of Bismuth Telluride Thin Films

“…Intuitively, the expected propensity of WF was thought to increase as the contents of Te increased because the WFs of Te and bismuth telluride were reported with higher values than Bi [50,51]. The reported WF values of Bi, Te, Bi oxide and Te oxide are listed in Table 5 [50][51][52][53][54]. In other words, the WFs were expected to be BT70 > BT50 > BT30 > and BT20; however, our experimental findings deviated from such anticipation.…”

Synthesis of a Tellurium Semiconductor with an Organic–Inorganic Hybrid Passivation Layer for High-Performance p-Type Thin Film Transistors

“…Figure a–d shows the XPS spectra of the Te thin film without passivation layer (pristine), with Al 2 O 3 passivation layer, SU-8 polymeric template, and Al 2 O 3 -infiltrated SU-8 passivation layer, respectively. The deconvoluted Te 3d peaks in the XPS spectrum of the pristine Te thin film were observed at 583.5 and 573.1 eV, corresponding to the Te 3d 3/2 and Te 3d 5/2 bonds, respectively, and the oxidation states, Te 4+ 3d 3/2 and Te 4+ 3d 5/2 peaks arising from the TeO 2 component, were observed at higher binding energies of 586.7 and 576.2 eV, respectively. , The oxidation of neutral Te to the Te 4+ state can be attributed to the thermal annealing process after the deposition of Te thin film . In the case of the Te thin film passivated with the Al 2 O 3 passivation layer, the Te 4+ peaks were not observed and were below the detection limit in the XPS Te 3d 5/2 core level, indicating the deoxidization of TeO 2 states caused by the deposition of the Al 2 O 3 passivation layer.…”

“…Figure 5a− oxidation states, Te 4+ 3d 3/2 and Te 4+ 3d 5/2 peaks arising from the TeO 2 component, were observed at higher binding energies of 586.7 and 576.2 eV, respectively. 46,47 The oxidation of neutral Te to the Te 4+ state can be attributed to the thermal annealing process after the deposition of Te thin film. 40 In the case of the Te thin film passivated with the Al 2 O 3 passivation layer, the Te 4+ peaks were not observed and were below the detection limit in the XPS Te The phonon vibration and optical characteristics of the Te thin film with or without an Al 2 O 3 passivation layer, SU-8 polymeric template, and Al 2 O 3 -infiltrated SU-8 passivation layer were investigated by Raman spectroscopy.…”

Designing dual-emission phosphors for temperature warning indication and dual-mode luminescence thermometry

“…3(a), the presence of Sr, Gd, Li, Te, O, Tb, Mn, and C elements was confirmed by analyzing the XPS survey scan spectrum. 34 Fig. 3(b) shows the core-level XPS spectrum of Te 3d.…”