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Wang Q.,Tokushima University | Wang Q.,Dalian University of Technology | Tamai K.,Tokushima University | Miyashita T.,SAMCO Inc. | And 4 more authors.
Japanese Journal of Applied Physics | Year: 2013

To gain a flat recess profile with uniform etching depth, dry recess experiment with different inductively coupled plasma (ICP) etching conditions was done on an AlGaN/GaN heterostructure. Trenching effect at the bottom near the sidewall was observed when positive photoresist was utilized and the ICP power was low. The recess profile was improved by adopting SiO2 as the etching mask and increasing the ICP power. GaN metal-oxide-semiconductor field-effect transistors (MOSFETs) on AlGaN/GaN heterostructure with different gate recess conditions were fabricated and characterized. The maximum field-effect mobility of 152.8 cm-2 V-1 s-1 and the minimum interface state density of 1.39 × 1011 cm -2 eV-1 were obtained from the optimized gate recess condition with ICP power of 100 W, bias power of 20W and etching mask of SiO2. © 2013 The Japan Society of Applied Physics.


Jiang Y.,Tokushima University | Jiang Y.,Dalian University of Technology | Wang Q.P.,Tokushima University | Wang Q.P.,Dalian University of Technology | And 6 more authors.
Journal of Physics: Conference Series | Year: 2013

The dry recessed-gate GaN metal-oxide-semiconductor field-effect transistors (MOSFETs) on AlGaN/GaN heterostructure using boron trichloride (BCl3) as etching gas were fabricated and characterized. Etching with different etching power was conducted. Devices with silicon tetrachloride (SiCl4) etching gas were also prepared for comparison. Field-effect mobility and interface state density were extracted from current-voltage (I-V) characteristics. GaN MOSFETs on AlGaN/GaN heterostructure with BCl3 based dry recess achieved a high maximum electron mobility of 141.5 cm 2V-1s-1 and a low interface state density.


Wang Q.,Dalian University of Technology | Wang Q.,Tokushima University | Jiang Y.,Dalian University of Technology | Jiang Y.,Tokushima University | And 7 more authors.
Solid-State Electronics | Year: 2014

GaN metal-oxide-semiconductor field-effect transistors (MOSFETs) with recessed gate on AlGaN/GaN heterostructure are reported in which the drain and source ohmic contacts were fabricated on the AlGaN/GaN heterostructure and the electron channel was formed on the GaN buffer layer by removing the AlGaN barrier layer. Negative threshold voltages were commonly observed in all devices. To investigate the reasons of the negative threshold voltages, different oxide thickness, etching gas and bias power of inductively-coupled plasma (ICP) system were utilized in the fabrication process of the GaN MOSFETs. It is found that positive charges of around 1 × 1012 q/cm 2 exist near the interface at the just threshold condition in both silane- and tetraethylorthosilicate (TEOS)-based devices. It is also found that the threshold voltages do not obviously change with the different etching gas (SiCl4, BCl3 and two-step etching of SiCl 4/Cl2) at the same ICP bias power level (20-25 W) and will become deeper when higher bias power is used in the dry recess process which may be related to the much serious ion bombardment damage. Furthermore, X-ray photoelectron spectroscopy (XPS) experiments were done to investigate the surface conditions. It is found that N 1s peaks become lower with higher bias power of the dry etching process. Also, silicon contamination was found and could be removed by HNO3/HF solution. It indicates that the nitrogen vacancies are mainly responsible for the negative threshold voltages rather than the silicon contamination. It demonstrates that optimization of the ICP recess conditions and improvement of the surface condition are still necessary to realize enhancement-mode GaN MOSFETs on AlGaN/GaN heterostructure. © 2014 Elsevier Ltd. All rights reserved.


Kusuda Y.,SAMCO Inc. | Nonaka T.,SAMCO Inc. | Motoyama S.,SAMCO Inc.
ECS Transactions | Year: 2012

SAMCO has developed process technology for deep silicon etching (DSE) using the Bosch Process (1), and depositing insulation film on sidewalls with cathode-coupled, liquid-source PECVD for "via-last" TSV processes (2). SAMCO's ICP DRIE system was used for deep silicon etching with excellent anisotropy for TSV applications, and SAMCO's cathode-coupled PECVD systems feature proprietary technology allowing the deposition of sidewall insulation films with excellent step coverage. © The Electrochemical Society.


Matsutani A.,Tokyo Institute of Technology | Hashidume Y.,Tokyo Institute of Technology | Ohtsuki H.,Samco Inc. | Koyama F.,Tokyo Institute of Technology
Japanese Journal of Applied Physics | Year: 2012

We demonstrated the fabrication of a Si-based high-index-contrast-grating (HCG) structure by thermal nanoimprint lithography and Cl 2/Xe- inductively coupled plasma (ICP) etching. A vertical etching profile and a smooth etched surface, which satisfy the requirements for optical device application, were obtained. We believe that this proposed process is useful for the microfabrication of Si-based optical devices, such as the HCG structure, photonic crystals, narrow optical waveguides, and micro-electro-mechanical systems (MEMS). © 2012 The Japan Society of Applied Physics.


Matsutani A.,Tokyo Institute of Technology | Ohtsuki H.,Samco Inc. | Koyama F.,Tokyo Institute of Technology
Japanese Journal of Applied Physics | Year: 2011

We investigated the Si dry etching process by inductively coupled plasma (ICP) using solid I2 as an etching gas source. A vertical etching profile and a smooth etched surface, which satisfy the requirements for optical device fabrication, were obtained at a relatively higher substrate temperature. The etching rate of Si was approximately 90 nm/min at 1 Pa and at an ICP/bias RF power of 300/100 W. The I2 plasma etching technique is a very simple C-, CF-, and H-free process. In addition, we believe that this proposed process is useful for fabricating Si-based optical devices, such as photonic crystals, narrow optical waveguides, and micro-electro-mechanical systems (MEMS). © 2011 The Japan Society of Applied Physics.


Patent
Samco Inc. | Date: 2015-06-04

The present invention provides a light beam measuring instrument that can securely receive light reflected by a sample. The light beam measuring instrument 1 includes an optical axis tilting mechanism 13 that includes a first tilting mechanism 131 and a second tilting mechanism 132. From the optical axis A1 of irradiation light beam emitted from a light beam source 112, the first tilting mechanism 131 tilts the optical axis A1 about the first tilting axis T1. The second tilting mechanism 132 tilts the optical axis A1 about the second tilting axis T2. The light beam measuring instrument 1 can receive the light reflected by the semiconductor chip C by means of operation of the optical axis tilting mechanism 13 even if the light reflected by the semiconductor chip C is tilted. Accordingly, this apparatus can securely perform measurement or inspection using the light beam.


Trademark
SAMCO Inc. | Date: 2012-10-16

Semiconductor manufacturing machines; semiconductor manufacturing systems comprised of semiconductor manufacturing machines.


Trademark
SAMCO Inc. | Date: 2012-10-16

Semiconductor manufacturing machines; semiconductor manufacturing systems comprised of semiconductor manufacturing machines.


Kashino J.,Tokyo Institute of Technology | Inoue S.,Tokyo Institute of Technology | Matsutani A.,Tokyo Institute of Technology | Ohtsuki H.,SAMCO Inc. | And 2 more authors.
2013 IEEE Photonics Conference, IPC 2013 | Year: 2013

We demonstrate the transverse-mode control of 980nm VCSELs using highly angular dependent HCG mirrors. The fabricated a-Si HCG clearly shows the large angular dependence of reflectivity, which enables single transverse-mode operations of large-area VCSELs. © 2013 IEEE.

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