标题: | 单层及多层金属薄膜与p型锑化镓接触之特性分析 Characterization of Single-layer and Multi-layer Metal Films Contacts on P-Type Gallium Antimonide |
作者: | 郑宇杰 林健正 Cheng, Yu-Chieh Lin, Chien-Cheng 材料科学与工程学系所 |
关键字: | 三五族化合物半导体;锑化镓;欧姆接触;多层金属;III-V compound semiconductor;GaSb;ohmic contact;multi-layer metal |
公开日期: | 2017 |
摘要: | 随着元件尺寸的不断微缩,产生的物理极限使得矽基互补式金属氧化物半导体(CMOS),难以继续提升其元件效能。近年来许多新的替代材料,以及元件结构新技术的引进,让电晶体的效能有了新的进步方向。其中三五族化合物半导体比起矽有更高的载子迁移率,使其元件在低电压供给下,能够有高的电流表现,提升效能。而比起其他三五族半导体材料,锑化镓拥有较高的块材电洞迁移率,其电洞迁移率约为1000 cm 2/Vs,及其能障约为0.72eV,是适合取代矽应用于p-MOSFETs 的材料。 为了达到三五金氧半电晶体的高效能,其中主要的挑战是形成低电阻之汲极/源极接面(S/D),然而锑化镓与金属接触介面的技术仍未完整建立,由于锑化镓可达之低掺杂浓度和高退火活化温度,在锑化镓p-MOSFET之制程中,金属与锑化镓的合金为S/D的自我对准制程是必要的。 本论文研究金属薄膜与锑化镓接触之材料反应机制,以及电性分析。金属薄膜的选择为单层金属Ni、Ti、Co和双层金属Ti/Ni、Ni/Ti,在200~600°C ∕30秒 快速热退火处理后,以TEM/EDS、XRD 和 AFM进行材料分析,并以圆形传输线模型结构萃取特征接触电阻。 在研究中发现,高温退火下,接触电阻会因相分离的产生而大幅上升。本研究得到锑化镓与金属薄膜之最低接触电阻5.3×〖10〗^(-5) Ω-cm2,为Ti/Ni 与GaSb接触,退火条件为500°C∕30秒,其中微晶的TiNi 反应层产生,并与锑化镓基板接触。研究结果得知,为达到低电阻之金属/锑化镓合金S/D的形成,制程上需要低的热预算,并维持足够低的温度以避免相分离产生。 As the scaling of device continued shrinking, the Si-based complementary metal-oxide-semiconductor (CMOS) has faced difficulties in enhance the device performance due to the physical limitation. For the past few years, the introduction of alternative materials and device structures are expected to improve the device performance. III–V compound semiconductor materials have higher carrier mobility compared with Si, which lead to the higher device performance at low power supply. Among the III–V compound semiconductor materials, GaSb has the bulk hole mobility of ~1000 cm2/Vs, higher than that of most other III–V compounds, as well as a sufficiently large band gap (0.72 eV), which is promising to replace Si as the materials of the transistors. One of the main challenges to achieve the high performance of III-V pMOSFETs is the low-resistance source and drain (S/D) formation. However, the fabrication of high-performance GaSb-based pMOSFETs is difficult owing to the metal/GaSb source/drain contact technologies. Because of the low dopant solubility and high temperature of dopant activation annealing of GaSb, self-aligned metal S/D formation process is necessary for the fabrication process of GaSb-based p-MOSFETs. In this work, the reaction mechanisms and electrical properties of metal films contacts on p-GaSb were characterized. Ni, Co and Ti were used to be materials of the single-layer metal films and the combinations of Ti/Ni and Ni/Ti were used for the multi-layer metal films. The metal-GaSb alloys formed at the interface of the contacts by rapid thermal annealing process (200~600°C / 30s) have been characterized using transmission electron microscopy/energy dispersive spectromter (TEM/EDS), x-ray diffraction (XRD) and atomic force microscopy (AFM). The specific contact resistance of the contacts of metal films on p-GaSb were extracted by circular transmission line model (CTLM). The specific contact resistance increased extremely when the samples were annealed at high temperature due to the phase separation at the interface of contact. The lowest specific contact resistance was measured as 5.3×〖10〗^(-5) Ω-cm2 at the contact of Ti/Ni on p-GaSb annealed at 500°C / 30s compared with other samples. These results indicated that in order to develop the metal-GaSb alloys S/D with low parasitic resistance, the processing temperature should be controlled specifically lower than the temperature of phase separation. |
URI: | http://etd.lib.nctu.edu.tw/cdrfb3/record/nctu/#GT070451553 http://hdl.handle.net/11536/141813 |
显示于类别: | Thesis |