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High breakdown voltage and high frequency field-effect transistors on heteroepitaxial diamond film.

异质外延金刚石薄膜上的高击穿电压和高频场效应晶体管。

基本信息

批准号：
10450127
负责人：
KAWARADA Hiroshi
金额：
$ 8.64万
依托单位：
Waseda University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

For the realization of high performance diamond electronic devices such as high power and high frequency transistors, FETs have been fabricated on hydrogen-terminated diamond surface conductive layer. In order to improve the performance of FETs, self-aligned gate fabrication processes which can reduce the gate length and parasitic resistances have been developed. Utilizing self-aligned gate FET fabrication process, 1 μm Cu gate MESFET realizes high transconductance of 110 mS/mm. This value exceeds the transconductance of SiC-FETs and Si-nMOSFETs of equal gate size. High performance diamond MISFETs have been also realized utilizing the same process. CaF_2 insulator which does not generate the high interface states density between hydrogen-terminated diamond is utilized as gate insulator.The highest transconductance of 86 mS/mm is obtained in 1.2 μm gate length. The MISFET shows high channel mobility of more than 250 cm^2/Vs. This value is more than twice higher than that of inversion type SiC MOSFETs. The high channel mobility is explained by the screening effect.The RF performances of diamond MESFETs and MISFETs are measured for the first time. The cut-off frequency of 2 μm gate MESFET with transconductance of 70 mS/mm shows 2.2 GHz. On the other hand, much higher cut-off frequency of 11 GHz is realized in diamond MISFET with 0.7 μm gate length. This value is 5 times higher than 2 μm gate MESFETs. Utilizing MIS structure which has gate insulator capacitance in series to surface-channel capacitance, the source to gate capacitance is reduced half as much as that of diamond MESFET. This FET also shows highest fmax of 22 GHz and 15 dB of power gain is obtained at 2 GHz.

为了实现高性能金刚石电子器件，例如高功率和高频晶体管，已经在氢封端金刚石表面导电层上制造了FET。为了提高 FET 的性能，已经开发了可以减少栅极长度和寄生电阻的自对准栅极制造工艺。利用自对准栅极 FET 制造工艺，1 μm 铜栅极 MESFET 实现了 110 mS/mm 的高跨导。该值超过了相同栅极尺寸的 SiC-FET 和 Si-nMOSFET 的跨导。高性能金刚石 MISFET 也已利用相同的工艺实现。采用不会在氢端金刚石之间产生高界面态密度的CaF_2绝缘体作为栅极绝缘体。在1.2 μm栅极长度下获得了86 mS/mm的最高跨导。 MISFET 显示出超过 250 cm^2/Vs 的高沟道迁移率。该值比反转型 SiC MOSFET 高出两倍以上。高沟道迁移率是通过屏蔽效应来解释的。首次测量了金刚石 MESFET 和 MISFET 的 RF 性能。跨导为 70 mS/mm 的 2 μm 栅极 MESFET 的截止频率为 2.2 GHz。另一方面，栅极长度为 0.7 μm 的金刚石 MISFET 实现了更高的 11 GHz 截止频率。该值比 2 μm 栅极 MESFET 高 5 倍。采用栅极绝缘体电容与表面沟道电容串联的MIS结构，源极至栅极电容比金刚石MESFET减少一半。该 FET 还具有 22 GHz 的最高 fmax，并且在 2 GHz 时获得 15 dB 的功率增益。