From Longman Business Dictionary
dollarizationdol·lar·i·za·tion /ˌdɒləraɪˈzeɪʃənˌdɑːlərə-/ (also dollarisation British EnglishBrE) noun [uncountableU]ECONOMICS1when people in countries outside the US prefer to use the dollar, rather than their country’s own currencyHigh inflation has led many Russians to hold US dollars rather than roubles. This dollarisation is only now starting to reverse.
2FINANCEwhen a country makes its currency the same value as the dollar, or keeps its currency at the same rate in relation to the dollar —dollarized (also dollarised British EnglishBrE) adjectiveadjAs a dollarised economy, the Argentinian peso has the same value as the US dollar.