[19a-Z31-1~11] 17.3 Layered materials

▼ [19a-Z31-6] Mobility enhancement of p-SnS/h-BN heterostructure FET by Ti contact reaction

〇(D)YihRen Chang¹, Takashi Taniguchi², Kenji Watanabe², Tomonori Nishimura¹, Kosuke Nagashio¹ (1.UTokyo, 2.NIMS)

Keywords:SnS, p-FET

2D materials resistant to short channel effect have enjoyed remarkable achievement in n-type FET performance such as reasonable mobility, low subthreshold swing, and high on-current. However, the development of p-type counterpart, required for complementary operation, is still in demand owing to intrinsic n-type channel by defect-generated electrons and Fermi level pinning to the conduction band. Here, SnS possesses high potential as high performancehigh-performance p-channel < 5 nm other than already well explored WSe₂, because low effective mass is expected due to s orbital of Sn for valence band maximum. Recently, PLD grown SnS has been reported to achieve current on/off ratio > 10⁶ in 4 nm-thick FET, while the mobility of ~1 cm²V^-1s^-1 was rather low due to low crystallinity caused by high energy deposition.[1] In this work, SnS was directly grown on top of h-BN flakes by thermal PVD to enhance the crystallinity and the device performance of SnS FETs. By solving oxidation issue with Ti deposition under UHV condition, 2-probe field effect mobility of ~23.8 cm²V^-1s^-1 is achieved in 4.2 nm-thick SnS/h-BN FET.