Plasma Deposited Silicon Nitride for Indium Phosphide Encapsulation

Abstract

The composition and annealing characteristics of plasma deposited silicon nitride encapsulating films on ion implanted indium phosphide have been investigate d . X-ray photoelectron spectroscopy was employed to study the surface of InP substrates cleaned with organic solvents and HF or HIO3 solutions prior to encapsulation. The composition of silicon nitride films deposited with 13.56 MHz RF excitation was determined through Auger electron spectroscopy and infrared spectroscopy both before and after annealing. The hydrogen concentration decreased from 21 to 9% during annealing. InP substrates implanted with silicon at 100 keV to a dose of 5 • 1012 cm -2 and 150 keV to a dose of 3 • 1012 cm -2 had activations of approximately 60% after annealing at 700~ X-ray photoelectron spectroscopic measurements were performed at five depths through the silicon nitride/indium phosphide interface of an annealed and an unannealed sample. No chemical interaction between the film and the substrate was observed before or after annealing. However, a change in the composition of the interfacial native oxides upon annealing is suggested from differences between the oxygen peaks for the unannealed and annealed samples.There is considerable interest in the fabrication of devices and integrated circuits on indium phosphide (InP) substrates. This interest primarily derives from the large saturated drift velocity of electrons in InP and from the lower density of surface states at an insulator/InP interface than at an insulator/GaAs interface, which allows the fabrication of accumulation mode metal-insulator-semiconductor devices (1, 2). The thermal instability of InP at temperatures greater than 362~ (3) creates great difficulties for the development of a technology for doping InP through diffusion. Ion implantation, with its benefits of good control and reproducibility and its potential for allowing a planar and possibly self-aligned (4) fabrication technology, is an attractive alternative to diffusion or epitaxy. Since ion implantation disorders the crystal lattice and since the implanted species must be activated, it is necessary to anneal the substrate after implantation. The temperatures at which good implant activation can be achieved are sufficient to cause incongruent evaporation of the surface of the InP substrate (5). Surface protection can be achieved through the use of a thin encapsulating layer. Plasma deposited silicon nitride films are of particular interest as they are deposited at low temperatures (6). Among the properties of a good encapsulant are good adhesion to the substrate, resistance to cracking and blistering, and no chemical interaction with the substrate (5).The ability of a film to meet the adhesion requirements is related to the stress in the film and to the characteristics of the film-substrate interface which will be dependent on the InP cleaning procedure. We present here the results of a study of two procedures for cleaning InP substrates prior to encapsulation with plasma-deposited silicon nitride. The sil...

The Low Temperature Catalyzed Chemical Vapor Deposition and Characterization of Silicon Nitride Thin Films

“…Low temperature dielectric film growth may also be desired in silicon processing schemes where thermal budgeting is a major consideration. Plasma-enhanced chemical vapor deposition (PECVD) (1)(2)(3)(4), remote plasma-enhanced chemical vapor deposition (RPECVD) (5)(6)(7)(8)(9), photochemical vapor deposition (PVD) (10), and electron cyclotron resonance (ECR) microwave plasma-enhanced chemical vapor deposition (MPECVD) (11)(12) all employ energy inputs that stimulate the nonthermal production of reactive intermediates from the initial feed reactants. These reactive intermediates, which can consist of excited molecules, atoms, and radicals, then react to form the dielectric films on substrates maintained at low temperatures.…”

Synthesis and characterization of glass-ceramic Bi2-xGaxSr2Ca2Cu3O10+ysuperconductors

“…Comparing the results obtained for different compositions of BiSrCaCuO material, including different doping/substitution cases, the E a was found to range from 75 to 355 kJ mol −1 [51][52][53]. However, in this work, substitution of gallium, particularly for x = 0.2, 0.8 and 1.0 samples, increased the E a value either by changing the diffusion mechanism within the solubility limit of the BiSrCaCuO material for Ga atoms or by providing a variation in the bonding distance between the BiO-GaO layers.…”

Silicon Dioxide with a Silicon Interfacial Layer as an Insulating Gate For Highly Stable Indium Phosphide Metal‐Insulator‐Semiconductor Field Effect Transistors

“…The 30 min CF4 plasma cleaning was necessary to remove the film deposits on the chamber walls from previous deposition runs. Our previous experiments (17,18) have indicated that 30 min were long enough for the removal of the films from prior runs. Then the substrates were loaded into the chamber immediately after the initial clean to minimize any native oxide growth.…”

“…The substrates were initially cleaned according to the following procedure (17). The samples were first degreased and then dipped for 30 s each in solutions of (1:1:4)12:1 (NCl:HF:H20):H20= (solution A) followed by 10% H3PO4 in deionized (DI) H20 (solution B).…”

“…An argon ion beam was used for surface cleaning which was operated at 2 keV. The details of the XPS technique as applied to insulator/InP interfaces have recently been reported (17,18).…”