Reactive ion etching of silicon using bromine containing plasmas

Abstract

The characteristics of Si and SiO2 etching in HBr reactive ion etching plasmas have been studied by measuring etch rates, optical emission, scanning electron microscopy (SEM) cross-sectional analysis, and x-ray photoelectron spectroscopy (XPS). Etch rate measurements indicate that SiO2 is etched very slowly compared with Si, so that the Si/SiO2 etch selectivity may be as high as 400. Optical emission spectroscopy has been used to examine the gas phase species in the plasma, and emission from excited atomic bromine has been identified. The composition and thickness of reaction layers on silicon surfaces resulting from exposure to HBr plasmas has been obtained by XPS. It is found that the reaction layer on silicon due to HBr reactive ion etching is typically very thin, of the order of 1 monolayer thick. XPS has also been used to investigate the reaction layers on the sidewalls of etched trenches, and a thin oxidized layer has been detected for oxide-masked Si trench etching.

Electron-Induced Surface Reactions of η3-Allyl Ruthenium Tricarbonyl Bromide [(η3-C3H5)Ru(CO)3Br]: Contrasting the Behavior of Different Ligands

“…In this respect, [(η 3 -C 3 H 5 )Ru(CO) 3 Br] would be preferred over [(η 3 -C 3 H 5 )Ru(CO) 3 Cl] because Br is far less efficient at etching Si or the native oxide layer typically present on Si surfaces as compared to Cl. 46,47 Finally, it should be noted that the findings from the present study, notably the preferential ejection of CO ligands in the precursor decomposition step (stage 1), coupled with the ability of post-deposition electron beam processing to remove adsorbed halogen atoms (stage 2), may help to explain why ClAuCO has been used to deposit pure Au nanostructures using EBID via the following reaction sequence. 48 V. CONCLUSIONS Surface bound η 3 -allyl ruthenium tricarbonyl bromide [(η 3 -C 3 H 5 )Ru(CO) 3 Br] molecules are decomposed by electron irradiation in a process that initially reduces the central metal (Ru) atoms and ejects CO ligands into the gas phase, and the carbon atoms contained within the η 3 -allyl (η 3 -C 3 H 5 ) ligand are incorporated into the metal-containing deposit that forms.…”

Etch profile control of high-aspect ratio deep submicrometer α-Si gate etch

“…Since the subsequent ME is highly selective to oxide, this BT step is critical in preventing micromasking. To improve etch rate and minimize undercut, a chlorine and bromine gas mix was used in the ME step [1], [2]. The OE step was designed to achieve a very high etch selectivity over oxide (more than 100:1) utilizing mild ion bombardment to minimize gate oxide loss and damage.…”

“…With the decrease of gate oxide thickness, a highly selective low-damage etch is critical. The current solutions to these etch process problems can be roughly categorized into three areas: 1) process development and optimization; 2) hardware development; and 3) process modeling and control [1]- [8].…”

Silicon etching in a pulsed HBr/O2 plasma. II. Pattern transfer

“…[5][6][7][8][9][10][11][12][13] The fundamental mechanisms for Si and SiO 2 etching are summarized in the following, wherein a very small percentage of oxygen in the feed gas stock is considered. [5][6][7][8][9][10][11][12][13] The fundamental mechanisms for Si and SiO 2 etching are summarized in the following, wherein a very small percentage of oxygen in the feed gas stock is considered.…”