| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 102 === In this paper, in order to overcome the scale down issue, a novel metal oxide semiconductor field effect transistor with L-shaped channel structure (L-MOS) [1], and new L-shaped channel structure for SONOS-type nonvolatile memory (L-SONOS) are designed and studied. Besides, the several types of L-shaped structures are also demonstrated. Meanwhile, we use Fowler-Nordheim tunneling (FN tunneling) mechanism for memory''s program and erase, and analyses the memory window, retention time, endurance, and drain disturb.
Studied and compared with the conventional MOSFET device for the same average gate length (Lavg), the proposed device electrical characteristics are analyzed and evaluated by three dimension (3-D) Sentaurus TCAD simulators. It can be confirmed that the L-MOS device''s drain current(ID) have been improved more than 103 % as compared to that of Conv-MOS andthe device has lower drain-induced barrier lowering (DIBL) and subthreshold swing (S.S.) than its conventional counterpart has. In addition, the transconductance and voltage gain properties of the L-MOS are also improved 75.8 % and 70.9 % than its counterpart.
In addition, we analyze the electrical characteristics of the L-SONOS. Because of the L-shaped channel structure, L-SONOS reveals a better gate controllability. The memory window of it improves 50.89 % compare with Conv-SONOS, and better retention time performance has been seen. In addition, the Vth shift at drain disturb performance of the new device only falls 38.9 % compare to 65.3 % of the conventional device(Conv-SONOS) does. Although the L-SONOS''s endurance performance is lower than conventional one, the overall performance of the L-SONOS still can be said that it is a better SONOS memory device than its counterpart, Conv-SONOS.
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