橫向溝槽式功率二極體/金屬氧化物場效電晶體與p型氮化鎵功率高速電子遷移率場效電晶體關鍵製程開發

Critical process development in Lateral Trench Power Diodes / MOSFETs and p-GaN gate power HEMTs

林品澔(Pin-Hau Lin)

指導教授 ： 吳添立

國立交通大學/國際半導體產業學院/國際半導體產業學院/碩士(2020年)

摘要

功率元件發展朝向更大的功率密度、更低的功率消耗、更快的操作速度做開發，在本篇論文中製作絕緣矽基板橫向溝槽式功率元件及p型氮化鎵高電子遷移率電晶體，並探討了兩種功率元件的關鍵製程及電性量測結果。
以SOI基板做橫向溝槽式金氧半場效電晶體的製程開發；垂直結構能夠大幅增加元件的崩潰電壓，此製程開發能使深度1μm的崩潰電壓能增至89V；本論文也探討不同溝槽尺寸對金氧化場效電晶體及二極體的影響。
p型氮化鎵/氮化鋁鎵/氮化鎵的閘極結構為製作成增強型高速電子遷移率場效電晶體的方法之一，本論文開發p型氮化鎵的乾式蝕刻製程，透過硬式阻擋層厚度的增減將氮化鈦的側向蝕刻減少為30nm，也以通入氧氣提高閘極區域外p型氮化鎵/氮化鋁鎵的選擇比提升至39。元件以無金製程的做製程開發，降低了成本與汙染。電性量測上，發現鈍化層材料對p型氮化鎵元件有很大的影響，本論文在將氮化矽與氧化矽做比較時，發現鈍化層為氧化矽的元件起始電壓夠增加約5V。

關鍵字

功率元件 ； 溝槽式金氧化場效電晶體/二極體 ； 氮化鎵

並列摘要

Larger power density、 lower consumption and higher switching speed are the inspection on development of power devices. We developed two different kinds of power devices and analyze their characteristics in this thesis
We have fabricated Lateral Trench Metal on Semiconductor Field Effect Transistor on Silicon-on-Insulator wafer. We achieved 89V breakdown voltage with 1 µm-depthed Trench. Furthermore, we investigated the performance of trench MOSFET and diode with different dimension of trench.
p-GaN /AlGaN / GaN gate structure is one way to approach enhancement mode characteristic. In this thesis, we developed dry etching process for p-GaN with TiN / p-GaN / AlGaN / GaN gate structure. Besides, we reduced TiN sidewall etching into less than 50 nm and increased the selectivity of p-GaN / AlGaN up to 39 by adding Oxygen Plasma.
We also fabricated p-GaN/AlGaN/GaN HEMTS devices with Au-free process and analyzed their characteristics. We found that the material of passivation has huge influence for this structure. Compared SiN and SiO2 as the passivation, we found the latter can increase 5 V for threshold voltage.

並列關鍵字

Power Device ； Trench MOSFET ； GaN

參考文獻

[1] B. J. Baliga, Fundamentals of Power Semiconductor Devices, 2nd edition, Springer Science, 2019.

[2] H. Okumura, “A roadmap for future wide bandgap semiconductor power electronics,” in MRS Bull.(Power Electronics with Wide Bandgap Materials), vol. 40, no. 5, pp. 439-444, May 2015.

[3] T. Bouchet, “2018 GaN / Si a new era of energy conversion: road map and demonstrators”, in APEC (San Antonio, TX), Nov 2018.

[4] T. Kikkawa, K. Makiyama, T. Ohku, M. Kanamura, K. Imanishi, N. Hara, and K. Joshin, “ Current Status and Future Prospects of GaN HEMTs for High Power and High Frequency Application,” in ECS Trans, vol. 50, no. 3, p323-332, Nov 2013.

[5] A. Burenkov, and J. Lorenz, “On the role of corner effects in FinFETs,” Proceedings of the European Workshop on Ultimate Integration of Silicon, pp. 31-34, March 2003.