제안 방법

• The first silicon nitride whose thickness is about 1000 A was deposited to insulate between the bottom metal of MIM capacitors and the substrate which is 6 inch n-type GaAs wafer. After bottom metal site was developed by the first photolithography, the first seed metal used at Au plating was deposited by DC sputtering about Ti/Au (500A/1500 A)- Non-cyanide, sulfite-based gold plating solution was used in this study. At MIM capacitors, the bottom electrodes were made by the first Au plating, and then the insulator layers, the second silicon nitride thin films were deposited by PECVD whose conditions were three and were indicated at table 1.
• At PECVD process of this study, to manufacture the MIM capacitor with the high breakdown electric field, the refractive index of silicon nitride was decreased by SilWNHj gas mixing rate and then the density of silicon nitride was increased by working pressure and RF power. As the SiHi/NHj gas mixing rate is decreased, the Rms values of silicon nitride thin films are decreased and the breakdown electric fields are improved at MIM capacitor.
• In this study, MIM capacitors with 1000A PECVD silicon nitride were manufactured by SiHVNHj gas mixing rate, working pressure, and RF power of PECVD process at 3001二 At MIM capacitors, the surface roughness of insulator layer which is 1000A silicon nitride and is located on the bottom metal/1000 A silicon nitride is analyzed by Atomic Force Microscopy (ASM). Also, the refractive index of this silicon nitride is measured by ellipsometer, and the wet-etch rate was obtained by the wet-etch in Buffered Oxide Etching (6:1, BOE).
• In this study, we fabricated the excelled MIM capacitors of 1000 A silicon nitride with high breakdown electric field for InGaP/GaAs HBT Applications. There breakdown electric field and capacitance had about 7.
• The three PECVD process condition of insulator layer (silicon nitride layer) was summarized at table 1. The refractive index and the surface roughness of the silicon nitride thin films deposited by three conditions were respectively measured by ellipsometer and AFM, their wet-etch rate was obtained by the wet-etch in Buffered Oxide Etching (6:1, BOE).
• To analyze electrical and RF properties for our MIM capacitors, micro probe station (cascade 12000series) was interfaced with semiconductor parameter analyzer (Agilent 4156C), vector network analyzer (Agilent 8722ES) and impedance analyzer (Agilent 4284A) by which the breakdown electric Held, the self resonance frequency and the capacitance of our MIM capacitors were respectively identified.