FLIP-CHIP BONDING OF GaAs on Si SUBSTRATES AND ITS APPLICATION TO SEMICONDUCTOR LASERS

• Main Authors: PENG, SHENG-JIH, 彭顯智
• Other Authors: LEE CHIEN-PING
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/15637865982429348829

碩士 === 國立交通大學 === 電子研究所 === 84 === For enhancement of functionality and performance on a single substrate, hybrid integration of dissimilar materials has been an issue with increasingimportance. Much effort has been devoted to direct wafer bonding approachesin recent researches. For flip-chip bonding, the trend of using thin bonding materials with many advantages is reported. In this thesis, we propose the combination of bonding materials with ohmic contacts for devices. We use AU-Ge and Au-Be alloys which are ohmic metals for n- and p-type GaAs respectively. On the other hand, bonding with different materials on both sides (Au-Ge or Au-Be on GaAs with Au on Si) by wetting of low surface energymaterials (alloys) and two layer materials on Si (Au-Ge on Au on Si or Au- Beon Au on Si) are also considered. The first work is to find the optimum bonding condition for each material system by investigating the effects of bonding temperature, bonding time andmetallization thickness. Bonding is proceeded in a nearly oxygen-free ambientpreventing oxide formation with a proper pressure applied to the interfacefacilitating the reaction. Bonding is best achieved at 450~480 C for 8~10 minfor Au-Ge and 600~630 C for 8~10 min for Au-Be. The effect of melting point rise caused by interdiffusion is also observed. Second, we integrate GRIN-SCH-QW lasers to different metallizations on Sisubstrates---Au-Ge, Au, Au-Ge on Au, Au-Ge stripes on Au. Nearly identicalI-V curves and similar L-I characteristics to pre-bonding conditions are obtained, showing maintained laser performance and electrical properties. Good electrical interconnection through the formed bonds and ohmic contacts is well established. Thermal shocks between 77K and 70C cause no I- V curvedegradation up to 30~35 cycles. Further, lasers are bonded to both Au surfaces and Au-Ge stripes in etched Si V- grooves with 54.7 degree (111) smooth surfaces as reflection mirrors to exhibit surface-emitting behavior. Good thermal and mechanical properties are achieved. I-V curves that remain normal and L-I curves with comparablethreshold currents and quantum efficiencies measured right above together prove that this bonding technique is reliable in producing surface- emitting performance of laser light with good electrical properties.