Atomic Layer Deposition in MEMS Technology

Review Article: Recommended reading list of early publications on atomic layer deposition—Outcome of the “Virtual Project on the History of ALD”

“…The functionality (number of bonds formed during reaction with silica) of the reactant with five ligands RX 5 was not communicated in the abstract; the authors just state that they investigated it. Regarding the RX 4 -type compounds (commonly written today as ML 4 , i.e., metal with four ligands), it is mentioned that the reaction product depends on the quality and structure of the preexisting "layer" (layer within quotation marks in the original publication as well). The term "molecular layering" (Mokerekzhyoe yackabdaybe, transliterated as molekulyarnoye naslaivanie) is introduced.…”

“…Interaction of titanium and germanium tetrachlorides with hydrated silica, Shevjakov et al, 1967 This is a conference proceedings paper by Russian authors, dating from a conference in 1965, originally published in Russian (1967), and thereafter translated and published in English. 38 All the basic practical requirements of ALD can be identified: separate, saturating chemisorption reactions of TiCl 4 and H 2 O or GeCl 4 and H 2 O, absence of physical adsorption, purging of the reaction by-products by inert gas (in their case, O 2 ), and repeated reaction cycles (up to ten for TiCl 4 -H 2 O to make TiO 2 ). Cycles are denoted as "exposurepurging-hydrolysis-drying," and this sequence is repeated.…”

“…Cycles are denoted as "exposurepurging-hydrolysis-drying," and this sequence is repeated. Silica gel was treated with TiCl 4 and GeCl 4 at 180 C in air (pressure was not mentioned) and after the treatment the surface was treated with water vapor as long as HCl was released. This treatment (cycling) was repeated ALD-wise up to ten times.…”

“…ALE is commonly known as the origin of ALD, [1][2][3][4]6,8 while the work made under the name ML has remained relatively poorly known and cited. 2,4,6 A volunteer-based effort called virtual project on the history of ALD (VPHA) was launched in 2013 to make the early days of ALD more transparent. The invitation to participate in VPHA has been openly available since July 25, 2013, and is appended as supplementary material to this article.…”

“…[1][2][3][4][5][6][7][8] ALD has been discovered and developed independently at least twice under different names: molecular layering (ML) since the 1960s in the Soviet Union and atomic layer epitaxy (ALE) since 1974 in Finland. ALE is commonly known as the origin of ALD, [1][2][3][4]6,8 while the work made under the name ML has remained relatively poorly known and cited. 2,4,6 A volunteer-based effort called virtual project on the history of ALD (VPHA) was launched in 2013 to make the early days of ALD more transparent.…”