Gate quality of ex situ deposited Al/SiN_x:H/n-In_0.53Ga_0.47As devices after rapid thermal annealing

Abstract

Ex situ deposited SiN x :H/In 0.53 Ga 0.47 As metal-insulator-semiconductor devices, with a minimum of interface state density of 3.5 × 10 11 eV −1 cm −2 have been obtained by electron cyclotron resonance plasma method at a low substrate temperature (200 • C), after a rapid thermal annealing treatment. The effects of annealing temperature on interfacial and bulk electrical properties have been analysed using the C-V high-low frequency method and I-V measurements. The results show that, up to 600 • C, the annealing procedure gradually improves the interface properties of the devices. The frequency dispersion, the hysteresis and the interface trap density diminish, while the resistivity and the electrical breakdown field of the insulator film increase up to values of 8 × 10 15 cm and 4 MV cm −1 , respectively. We explain this behaviour in terms of the thermal relaxation and the reconstruction of the SiN x :H lattice and its interface with the In 0.53 Ga 0.47 As. At higher annealing temperatures, a sharp degradation of the structure occurs.

Electrical Characterization of Al/SiNx:H/n and p-In0.53Ga0.47As Structures by Deep-Level Transient Spectroscopy and Conductance Transient Techniques

“…Prior to dielec-tric deposition, a simple cleaning step was applied: substrates were ultrasonically degreased in trichlorethylene, acetone and propanol and deoxidized in HCl : H 2 O (1 : 3) for 1 min before drying in N 2 . In our previous work, 7) we reported on small-frequency-dispersion, small-hysteresis and very lowinterface-trap-density MIS structures that were obtained following this deposition procedure.…”

“…Indeed, improved values of resistivity and breakdown field are obtained when x increases. 7) Hence, x = 1.50 and x = 1.55 are the most suitable values for improving the electrical properties of the insulator bulk. Thus, we have used x = 1.50 as the best choice for the trade-off between interface quality and insulator electrical properties.…”

“…There are reports on MIS devices with good-quality interfaces based on SiN x :H/In 0.53 Ga 0.47 As structures in which the insulator was deposited by the electron-cyclotron-resonance plasma method (ECR). 6,7) Indeed, this is a low-temperature deposition method (200 • C or below) in which it is possible to reduce ion bombardment of the semiconductor surface during insulator deposition. However, ECR-deposited SiN x :H films have a relatively high H-concentration, making them thermally unstable.…”

Rapid thermally annealed plasma deposited SiNx:H thin films: Application to metal–insulator–semiconductor structures with Si, In0.53Ga0.47As, and InP

“…The deposition conditions were the same than those previously described for SiN x :H deposition, except the substrate temperature, that was now 200°C. 19,22,33 The thickness of the SiN x :H film was between 20 and 50 nm. After the RTA treatments, the samples were subjected to additional processing in order to fabricate the metal contacts.…”

“…17 In this article, we analyze in detail the influence of the RTA on the physical properties of ECR deposited SiN x :H films in a wide range of compositions-from Si-rich films to N-rich-and analyze the RTA effects on the SiN x :H/semiconductor interface with Si, [19][20][21] In 0.53 Ga 0. 47 As, 22,23 and InP. 24 -27 II.…”