| 摘要: | 本研究使用有機金屬化學氣相沉積法（Metal-Organic Chemical Vapor Deposition,
MOCVD），於高阻矽基板 Si(100) 上成長氮化硼（Boron Nitride, BN）薄膜，並探討不
同成長模式對其結構與電性表現之影響。成長模式主要分為連續氣流供應（Continuous
Flow, CF）與脈衝氣流供應（Pulsed Flow, PF），藉由控制氣體進入腔體的時序與流量，
調控BN薄膜在異質接面上的成核與堆疊機制。
結構分析方面，透過穿透式電子顯微鏡（TEM）、 X-ray 吸收光譜（XAS）與傅立葉轉換
紅外光譜（FTIR）等儀器，我們發現BN在 PF 模式下易形成亂層結構（turbostratic BN,
t-BN），而 CF 模式則傾向形成有序堆疊的六方結構 (hexagonal BN, h-BN)。t-BN與 Si
接面處具備較強的能帶偏折與界面重建能力，有利於二維電洞氣（2D Hole Gas, 2DHG）
的形成。根據低溫霍爾量測的結果，以PF成長的BN呈現較穩定的2DHG濃度及遷移
率，在 13K ~ 300K 的溫度範圍內，2DHG 的濃度及遷移率維持在 ~ 10¹⁵ cm⁻²、 ~50
cm²/V·s，並具備不隨溫度改變的遷移率，顯示其導電特性可能由介面載子累積層主導。
本研究結果證實，透過調控磊晶參數可有效誘發 BN/Si 異質結面之 2DHG 結構，對未
來發展高性能 P-channel 元件與氮化物異質整合技術具潛力，並提供後續磊晶製程與材
料工程之重要參考依據。;In this study, boron nitride (BN) thin films were grown on high-resistivity Si(100) substrates
using metal-organic chemical vapor deposition (MOCVD). The structural and electrical
properties of BN films under different growth conditions were systematically investigated.
Two precursor supply modes—continuous flow (CF) and pulsed flow (PF)—were compared,
with gas injection timing and flow rate modulation employed to control the nucleation and
stacking behavior of BN films at the heterointerface.
Structural analyses using transmission electron microscopy (TEM), X-ray absorption
spectroscopy (XAS), and Fourier-transform infrared spectroscopy (FTIR) confirmed that PF
growth tends to promote the formation of turbostratic BN (t-BN), while CF results in the
formation of well-ordered hexagonal BN (h-BN). The t-BN structure, particularly at the
BN/Si interface, exhibits significant band bending and interface reconstruction effects, which
are favorable for the formation of a two-dimensional hole gas (2DHG).
Further investigation via low-temperature Hall measurements revealed that PF-grown samples
exhibited high and thermally stable hole concentrations on the order of 10¹⁵ cm⁻².
Additionally, the hole mobility reached up to 51 cm²/V·s at room temperature and showed
minimal temperature dependence, suggesting that the transport characteristics are dominated
by an interface-accumulated carrier layer rather than thermally activated bulk conduction.
These results demonstrate that by precisely tuning the epitaxial growth parameters, it is
possible to effectively induce a 2DHG structure at the BN/Si heterointerface. This finding
provides a promising pathway for developing high-performance p-channel devices and
advancing heterointegration of BN-based materials, offering valuable guidance for future
epitaxy and materials engineering research. |
