Anisotropic plasma etching of polysilicon

Mogab, C. J.; Levinstein, H. J.

doi:10.1116/1.570549

Cited by 156 publications

(79 citation statements)

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“…In methyl based etches, it is believed that sidewall passivation does play a role in determination of the overall anisotropy. 24 Thus, variations in the input gas mixture (both its composition and its point of introduction into the plasma) 8,12 could be used to enhance anisotropy. The last two etch characteristics listed above often go hand in hand; i.e., surface stoichiometry and electronic damage can be highly correlated, although it is not unreasonable to have electronic damage from other defects (hydrogen passivation for instance).…”

Section: Resultsmentioning

confidence: 99%

Characterization of the CH4/H2/Ar high density plasma etching process for HgCdTe

Eddy

Leonhardt

Shamamian

et al. 1999

J. Electron. Mater.

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High density plasma etching of mercury cadmium telluride using CH 4 /H 2 /Ar plasma chemistries is investigated. Mass spectrometry is used to identify and monitor etch products evolving from the surface during plasma etching. The identifiable primary etch products are elemental Hg, TeH 2 , and Cd(CH 3 ) 2 . Their relative concentrations are monitored as ion and neutral fluxes (both in intensity and composition), ion energy and substrate temperature are varied. General insights are made into surface chemistry mechanisms of the etch process. These insights are evaluated by examining etch anisotropy and damage to the remaining semiconductor material. Regions of process parameter space best suited to moderate rate, anisotropic, low damage etching of HgCdTe are identified.

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Section: Resultsmentioning

confidence: 99%

Characterization of the CH4/H2/Ar high density plasma etching process for HgCdTe

Eddy

Leonhardt

Shamamian

et al. 1999

J. Electron. Mater.

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“…We can assume that the etching mechanism of Ge:P[L] can be explained by the charge transfer mechanism. 20 For an n-type semiconductor, the electron from conduction band tunnels through the potential barrier at the surface and reaches the chemisorbed F atom. The F atom is thus negatively charged to form a surface dipole involving the ionized donor atoms(P) in Ge, giving higher etch rate.…”

Section: Resultsmentioning

confidence: 99%

“…The RIE process parameters were: working pressure of 20 mTorr, RF power 100 W, and total gas flow of 30 sccm. A cooling system was used to keep the handle wafer at a constant temperature of 20 C throughout the etch process. Surface steps were measured using an Ambios XP-100 step-profilometer.…”

Section: Methodsmentioning

confidence: 99%

Precision plasma etching of Si, Ge, and Ge:P by SF6 with added O2

Wongwanitwattana¹,

Shah²,

Myronov³

et al. 2014

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The impact of the O 2 content in SF 6 -O 2 gas mixtures on the etch rate and sidewall profile of silicon (Si), germanium (Ge), and phosphorous doped germanium (Ge:P) in reactive ion etching has been studied. The characteristics of etch rate and sidewall profile are greatly affected by the O 2 content. Below 50% of O 2 content, a large variation in Ge etch rates is found compared to that of Si, but for O 2 content above 50% the etch rates follow relatively the same trend. Lightly doped Ge shows the highest etch rate at a O 2 concentration up to 20%. Sidewall angles range from a minimum of 80 to a maximum of 166 , with O 2 concentration of 20% yielding perfect anisotropic mesa etch. Also at this O 2 concentration, reasonable Si/Ge selectivity is possible. These observations indicate that by adjusting the O 2 concentration, precision plasma etching of Si, Ge, and Ge:P is possible.

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“…The high degree of anisotropy that is readily achieved suggests that ion bombardment tends to dominate the etch mechanism by enhancing the reaction with the chemisorbed SiCl 2 layer and/or enhancing product volatility. This is borne out by the fact that only a small loading effect is observed in these cases (53), while F-source plasmas (38,39) exhibit strong loading effects. The absence of a significant loading effect and controllable anisotropy makes Cl-source plasmas most attractive for Si etching.…”

Section: Introduction To Microlithographymentioning

confidence: 93%

“…The most commonly used gases have been Cl 2 , CC1 4 , CF 2 C1 2 , CF3CI, Br 2 and CF 3 Br (57) along with mixtures such as C1 2 /C 2 F 6 , C1 2 /CC1 4 , and C 2 F 6 /CF 3 C1. Of these, the most useful systems appear to be Cl 2 (52), C1 2 /C 2 F 6 and CF 3 C1/C 2 F 6 (53,54) where high etch rates (500 -6300) A/min for undoped and doped poly-Si and selectivity (Si/Si0 2 -10-50:1) have been observed. The active etchant in these plasmas is likely to be CI and Br atoms; however, ion bombardment plays a significant role in achieving high etch rates and anisotropy control (see Section 5.5.C.).…”

Section: Introduction To Microlithographymentioning

confidence: 97%