Rutile films grown by molecular beam epitaxy on GaN and AlGaN/GaN
Rutile films grown by molecular beam epitaxy on GaN and AlGaN/GaN
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DOI：
10.1116/1.1868672
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发表时间：
2005-03-01
影响因子：
1.4
通讯作者：
Speck, JS
中科院分区：
文献类型：
--
作者：
Hansen, PJ;Vaithyanathan, V;Speck, JS
采用分子束外延的方法在（0001）取向GaN和（0001）Al0.33Ga0.67N/GaN异质结构场效应晶体管（HFET）上生长了金红石结构的二氧化钛（TiO2）。x射线衍射显示（100）TiO2平行于（0001）（GaN(AlGaN)）和[001]（TiO2）平行于< 11 (2)bar0 >(GaN(AlGaN))， TiO2有三种旋转变体。在GaN和AlGaN/GaN表面制备了50 nm厚的TiO2薄膜，透射电子显微镜显示，TiO2薄膜与半导体之间没有混合或反应。制备出与(10 (1)/ bar （TiO2）平行的柱状薄膜结构，横向畴尺寸为几纳米，平行于（10 (1)/ bar）（TiO2），横向畴尺寸为几十纳米。掺有TiO2的hfet的跨导率为140 MS/mm，比未掺有介质的hfet低约20%，且两种结构的针断电压相当。TiO2的介电常数近似于70。掺有TiO2的hfet的栅漏电流约为4 × 10(-6) mA/mm。50 V的电压，比50 V的电压大约低4个数量级。无介电介质的hfet。利用x射线光电子能谱进行波段偏移测量，发现金红石型TiO2与GaN的价带基本一致。(c) 2005年美国真空学会。
Titanium dioxide (TiO2, with the rutile structure) was grown on (0001) oriented GaN and (0001) Al0.33Ga0.67N/GaN heterostructure field effect transistor (HFET) structures by molecular beam epitaxy. X-ray diffraction showed (100)TiO2 parallel to (0001)(GaN(AlGaN)) and [001](TiO2) parallel to < 11 (2) over bar0 >(GaN(AlGaN)) with three rotational variants of the TiO2. Transmission electron microscopy of 50 nm thick TiO2 films on GaN and AlGaN/GaN showed sharp interfaces with no intermixing or reaction between the oxide and semiconductor. The TiO2 exhibited a columnar film microstructure with a lateral domain size of a few nanometers parallel to (10 (1) over bar)(TiO2) and a few tens of nanometers parallel to 00160 2 2 Metal-oxide HFIAs with 50 nm thick TiO2 dielectric layers under the gate were processed and compared to HFETs without the TiO2 dielectric layer. The transconductance of the HFETs with TiO2 was 140 MS/mm, approximately 20% less than HFETs with no dielecric, and the pinchoff voltages of the two stuctures were comparable. The dielectric constant of the TiO2 was similar to 70. The gate leakage current of the HFETs with ,TiO2, similar to 4 X 10(-6) mA/mm at. 50 V, was approximately 4 orders of magnitude lower than that of the. HFETs with no dielectric. Band offset measurements were performed using x-ray photoelectron spectroscopy, and the valence band of the rutile TiO2 and the GaN nearly line up. (c) 2005 American Vacuum Society.