N_2O等离子体处理对富硅氮化硅薄膜发光的影响

Effect of N_2O Plasma Treatment on Luminescence of Silicon-rich Silicon Nitride Films

采用PECVD方法制备富硅氮化硅(SiNx)薄膜,并研究了N2O等离子体处理对SiNx薄膜光致发光(PL)及电致发光(EL)的影响。研究结果表明,N2O等离子体处理前后SiNx薄膜的PL发光峰均位于430nm处,且强度变化不大。而其EL发光峰位于600nm处,处理后强度有所提高。但经过高温热处理后,EL强度会大幅度降低。这主要是由于N2O等离子体处理在薄膜中引入N原子,这些N原子与Si原子结合,消除Si的悬挂键,降低了非辐射复合中心的浓度;而热处理后发生的原子重排,使得N原子与Si原子断开,进而与O原子结合,致使EL强度降低。

Silicon-rich silicon nitride （SRSN） films were deposited on p-type silicon substrates using a conventional PECVD system. After deposition, SRSN films were treated by N2O plasma in the PECVD system. And MIS structure devices were fabricated using ITO as anode and a 300nm Al film as cathode. It was found that the N2O plasma treatment enhanced the electroluminescence of the SRSN MIS devices. However, the enhanced EL would be decreased by hightemperature annealing. The enhanced EL was attributed to the decreasing of Si dangling bonds by re-bonding with N atoms introduced by N2O plasma treatment. And after high-temperature annealing, the breaking of Si-N bonding resulted in the decreasing of EL of the SRSN MIS devices.