Two‐Dimensional Aluminum Diffusion in Silicon: Experimental Results and Simulations

Abstract

Two-dimensional diffusion of aluminum implanted through a mask in silicon has been measured after furnace or rapid thermal annealings. Chemical staining on cross-sectioned samples was used to determine both the vertical and the lateral junction depths. The spreading resistance standard procedure was adopted to measure the vertical profiles while a new procedure was developed for the determination of the lateral diffusion profiles. The difference in the measured profile by staining and spreading resistance is related to the spilling phenomenon that distorts the carrier concentration profile on beveled samples. Moreover, experimentally aluminum diffusion parameters and segregation coefficient at the Si/SiQ interface have been introduced in advanced one-dimensional (SUPREM III) and two-dimensional (SUPREM IV) process simulators. The good agreement between the simulated and the experimental data, for both the lateral and the vertical directions, indicates that these process simulators can reproduce with accuracy the aluminum diffusion.

Electron beam induced current microscopy investigation of GaN nanowire arrays grown on Si substrates

“…It is likely that this procedure induces the diffusion of Al deep into the Si wafer. Al diffusion in Si has been investigated in the literature [36,37]. The small size of the Al atom leads to a rather high diffusion coefficient.…”

Dark Current Spectroscopy of Transition Metals in CMOS Image Sensors

“…Due to its position in the periodic Table, Al is a shallow acceptor, commonly used for silicon doping when deep-diffused p-type regions are required. 50 As a shallow acceptor, Al is not effective for carrier generation and hence no significant impact of Al on image sensor performances is expected. Table III collects the results of the best-fit procedure of dark current data according to Eq.…”

A complementary bipolar technology family with a Vertically Integrated PNP for high-frequency analog applications

“…The counter doping requires a p-type dopant which needs to diffuse down to merge with the boron buried layer. Aluminum is a p-type dopant in silicon and has a diffusion coefficient that is about an order of magnitude higher than that of boron [41]- [44]. Boron implants were also used for the formation of the shallow region of the P well.…”

“…The epitaxial layer thickness was increased to 13.5 m and hence the thick n-type epitaxial layer has to be compensated to form the p-well for the PNP device. The key issues with aluminum are its very high diffusivity (an order of magnitude higher than boron) and low electrical activity, i.e., approximately, only 1/40 of the implanted dose becomes activated following the well drive [43], [44].…”