AVS 62nd International Symposium & Exhibition
    Electronic Materials and Processing Wednesday Sessions
       Session EM+AS+MS+SS-WeA

Paper EM+AS+MS+SS-WeA11
Nitrogen as a Source of Negative Fixed Charge for Enhancement Mode Al2O3/GaN Device Operation

Wednesday, October 21, 2015, 5:40 pm, Room 211C

Session: Surface and Interface Challenges in Wide Bandgap Materials
Presenter: MuhammadAdi Negara, Stanford University
Authors: M. Negara, Stanford University
R. Long, Stanford University
D. Zhernokletov, Stanford University
P.C. McIntyre, Stanford University
Correspondent: Click to Email

In recent years, significant research efforts have focused on developing enhancement mode (E-mode) GaN-based devices fueled by many potential applications. Simpler power amplifier circuits using a single polarity voltage supply and increased safety using a normally-off device can be achieved using E-mode devices leading to lower cost and an improvement of system reliability. Using the combination of E-mode and depletion mode (D-mode) devices in direct coupled logic open up also new applications for nitride semiconductors. To realize normally-off operation of GaN transistors, several approaches have been reported in the past including recessed gate structures [1], p-type gate injection [2], fluorine plasma treatment [3], surface channel GaN [4], thermally oxidized gate insulator [5] and oxide charge engineering [6]. In this report, nitrogen impurities introduced during atomic layer deposition of an Al2O3 gate dielectric are investigated as a means of modifying the threshold voltage (Vth)/flat band voltage (Vfb) of GaN MOS devices. As reported in reference [7], nitrogen may incorporate on either cation or anion substitutional sites or on interstitial sites in Al2O3 and become a source of negative fixed charge within Al2O3. The effectiveness of this approach for fixed charge modification of ALD-grown Al2O3 compared to several alternative approaches will be presented.

References:

[1] W. B. Lanford, et al., Electron. Lett. 41, no. 7, 449 (2005).

[2] Y. Uemoto, et al., IEEE Trans. Elect. Dev. 54, no. 12, 3393 (2007).

[3] Zhang et al., Appl. Phys. Lett. 103, 033524 (2013).

[4] W. Huang, et al., IEEE Elect. Dev. Lett. 27, no. 10, 796 (2006).

[5] K. Inoue et al., Elect. Dev. Meet., IEDM Technical Digest. International, pp. 25.2.1 (2001).

[6] B. Lu, et al., in Proc. Int. Workshop Nitride Semicond. Abstr.,536 (2008)..

[7] Choi et al., Appl. Phys. Lett. 102, 142902 (2013).