High pressure sputtering as a viable technique for future high permittivity dielectric on III–V integration: GdOx on InP demonstration

Abstract

Articles you may be interested inOptimization of in situ plasma oxidation of metallic gadolinium thin films deposited by high pressure sputtering on silicon J.The electrical properties of metal-oxide-semiconductor devices based on GdO x obtained by high pressure sputtering on InP substrates are studied. In order to prevent damage of the semiconductor substrate, an optimized two-step sputtering procedure has been used for the high permittivity dielectric deposition. First, a thin metallic Gd film was sputtered using a metallic Gd target and a pure Ar plasma. Then, without extracting the sample from the system, the GdO x films were obtained by plasma oxidation using an Ar/O 2 mixed atmosphere and reducing plasma power to minimize damage and interfacial regrowth. The resulting devices show fully functional capacitance curves. After forming gas annealing, the capacitors do not show interface regrowth up to a temperature of 500 C and the gate leakage stays within reasonable limits, below 2 Â 10 À4 Acm À2 at a gate voltage of 1.5 V. In addition, the interface trap density remains roughly constant with annealing temperature up to 400 C, in the low 10 13 eV À1 cm À2 range, decreasing for higher temperatures. At 550 C, the trap density is very low, under the detection limit of the conductance technique, but the devices show a severe capacitance reduction.

Scavenging effect on plasma oxidized Gd2O3grown by high pressure sputtering on Si and InP substrates

“…From the measured normalized conductance (not shown here) and using the conductance method, the D it value obtained is very high, in the order of 10 13 eV −1 cm −2 , but comparable with the one obtained with pure Pt gates [37] and with other works of Al 2 O 3 /InP capacitors [41]. It should be noticed that, in this study, no interfacial treatments were applied to the InP substrate before the HPS process, such as nitrogen plasma exposure [42] or Si capping [43].…”

“…This means a reduction in CET from 2.5 to 1.9 nm. In our previous works using Pt as top metal [37,38], this effect was not observed after the FGAs, so the capacitance increase can not be related to a change in the thickness of the dielectric material or to a permittivity increase. We can observe that the accumulation capacitance value does not change with frequency.…”

Thermal stability study of AlGaN/GaN MOS-HEMTs using Gd<inf>2</inf>O<inf>3</inf> as gate dielectric

“…The contact resistance (R c ) of the ohmic contacts and the sheet resistance (R sheet ) of the 2-dimensional electron gas were 0.86 Ω·mm and 263 Ω/□ respectively, calculated using transmission line method technique [10]. Prior to the gate metallization, half of the sample was covered by photo resist and on the other half, high pressure sputtered Gd 2 O 3 films [11,12] Several thermal treatments were conducted as described in Table 1. Before and after each treatment the same electrical measurements procedure was carried out on the devices at room temperature, including: thermal annealing at 500°C for 5 minutes; thermal cycle from room temperature (RT) to 425°C with a step of 100°C; and thermal storage at 500°C for one week in total.…”

Limitations of high pressure sputtering for amorphous silicon deposition

“…More recently, HPS has been used to deposit high permittivity dielectrics such as HfO 2 and Gd 2 O 3 [10][11][12]. However, high pressure plasmas are known to be a propitious environment for the formation of dust particles [13] that could be related with the presence of undesirable species in the plasma.…”