Processing Development for Making High Power Microwave 4H-SiC Devices

9711128饶本项目旨在发展半绝缘（SI）和半导体SiC的大功率和微波器件的加工技术。本文将深入研究SI - 4H-SiC中N离子和Al离子的注入以及N型4H-SiC外延层中Al离子的注入，以发展该材料的平面选择性区域掺杂技术。在SiC中进行砷注入以获得供体掺杂的探索性工作。由于N和P （As）给体在SiC中占据互补的晶格位置，N/P和N/As共植入将用于在SiC中获得高导电性的N(区。研究结果将有助于微波和大功率器件的接触电阻和体串联电阻的最小化，这是获得最佳器件性能的关键。微波和脉冲感应快速热加热装置将开发用于在高达1700℃的温度下退火2”直径植入SiC晶圆。植入/退火材料将通过van der Pauw Hall， SIMS，卢瑟福后向散射，TEM和光致发光测量进行彻底表征。这些测量将用于获得有关掺杂剂电活化、掺杂剂热稳定性、掺杂区晶格完美性和掺杂剂电离能等信息。为了在p型碳化硅表面实现高性能的欧姆接触，我们将尝试一种不同硅层和金属层厚度的新型欧姆接触金属体系（Si/Al/Si/Ti/Pt）。使用卤素灯快速热退火站在不同温度下对触点进行合金化。接触将通过TLM模式测量、扫描电镜、俄歇电子能谱和x射线衍射测量来表征。研究了高温大功率工作时触点的可靠性。肖特基和平面p-n结二极管将通过在SI和半导体4H-SiC中选择性区域植入而制成，并在高达500℃的不同温度下对I-V和C-V性能进行全面表征，将对二极管进行dlt测量以检测植入区域以及植入区域和SI衬底界面的深电平。利用本研究开发的最佳注入和欧姆接触条件，mesfet和jfet将分别以SI和n型4H-SiC材料制成，并在各种工作温度下充分表征其直流、微波和大功率性能，以及在高温下长时间工作的性能。拟议的工作将与位于纽约州Shenectady的通用电气研究中心、海军研究实验室、橡树岭国家实验室和国家标准与技术研究所的科学家合作进行。* * *

9711128 Rao This project is aimed at developing processing technology for high-power and microwave devices in semi-insulating (SI) and semi-conducting SiC. The N and Al ion implantations in SI 4H-SiC and Al ion implantation in n-type 4H-SiC epitaxial layers will be thoroughly pursued in order to develop planar selective area doping technology in this material. Exploratory work on As-implantation to obtain donor doping in SiC will be performed. Due to the complementary lattice positions occupied by N and P (As) donors in SiC, N/P and N/As coimplantations will be used to obtain highly conductive n( regions in SiC. Results of the coimplantation work will be useful for minimizing contact and bulk series resistances of microwave and high power devices, which is crucial for obtaining optimal device performance. Microwave and pulsed induction rapid thermal heating set-ups will be developed to anneal 2" diameter implanted SiC wafers at temperatures as high as 1700 (C. The implanted/annealed material will be thoroughly characterized by van der Pauw Hall, SIMS, Rutherford Backscattering, TEM, and photoluminescence measurements. These measurements will be used to gain information about dopant electrical activation, dopant thermal stability, doped region lattice perfection, and ionization energy of the dopants, etc. A new ohmic contact metal system (Si/Al/Si/Ti/Pt) with different Si and metal layer thicknesses will be tried to achieve high performance ohmic contacts on p-type SiC. Contacts will be alloyed at different temperatures using a halogen lamp rapid thermal annealing station. The contacts will be characterized by TLM pattern measurements, SEM, Auger electron spectrometry, and x-ray diffraction measurements. The reliability of the contacts for high-temperature and high-power operation will be studied. Schottky and planar p-n junction diodes will be made by selective area implantation in SI and semi-conducting 4H-SiC and thoroughly characterized for I-V and C-V performance at various temperatures up to 500 (C. DLTS measurements will be performed on the diodes to detect deep levels in the implanted region and at the interface of the implanted region and the SI substrate. Using the optimum implantation and ohmic contact conditions developed in this work, MESFETs and JFETs will be made in SI and n-type 4H-SiC respectively, and thoroughly characterized for their DC, microwave, and high-power performance at various operating temperatures and also for extended period operation at high temperatures. The proposed work will be performed in collaboration with the scientists at General Electric Research Center, Shenectady, NY, Naval Research Laboratory, Oak Ridge National Laboratory, and the National Institute of Standards and Technology. ***