薄（≦6.0nm）氮氧化矽層之製備藉由N2O電漿回火處理

Abstract

在本論文中，我們利用低壓化學氣相沈積系統於複晶矽及單晶矽薄膜上沈積氮化矽層，並利用N2O電漿及氣體進行退火處理，藉以分析此介電層之電性及物性之變化。結果顯示經由N2O電漿及氣體進行退火處理之後，會形成一氮氧化矽層，進而改善此介電層之品質與可靠度。亦即，經由這些回火處理過後之氮氧化矽層具有較佳的電特性如較低的漏電流，及電子捕捉率以及較大的崩潰電場等。此外，N2O電漿回火處理比起N2O氣體快速退火處理具有較好的厚度控制性。也就是說，N2O氣體快速退火處理在等效厚度的增加會隨著氮化矽層厚度增加而減少，但N2O電漿回火處理並不受此影響，經過50瓦五分鐘的N2O電漿回火處理後，會有1nm平均厚度的增加。 此外，N2O電漿回火處理比N2O氣體快速退火處理具有較大的崩潰電場，因此可為低溫回火處理製程上提供另一選擇。

In this thesis, we present a systematic study of interpoly LPCVD nitride and gate LPCVD nitride with the treatment of N2O plasma annealing and RTAN2O. The treatment of N2O plasma annealing or RTAN2O can cause reoxidation of the nitride film and form an oxynitride film or a nitride/oxide (N/O) stack film. Therefore, the samples with RTAN2O or N2O plasma annealing has higher breakdown field, lower leakage current, longer time-to-breakdown, and smaller gate voltage shift than the control samples, and the performance gets better as the increase of power for N2O plasma. In addition, the samples with N2O plasma annealing have more uniform increase in effective oxide thickness than those with RTAN2O. The rise in the effective oxide thickness for the samples with RTAN2O decreases gradually when the LPCVD nitride film becomes thicker. On the contrary, there will be an average increase of 5Å, 10Å, and 15Å in the effective oxide thickness after the treatment of 20W 5min, 50W 5min, and 100W 5min N2O plasma annealing. Besides, we get the larger breakdown field after the treatment of N2O plasma annealing than that with RTAN2O for both interpoly oxynitride and gate oxynitride films. This improvement for the samples with N2O plasma annealing should be due to the different reoxidation mechanism. Hence, N2O plasma annealing can provide another choice for low temperature annealing.