Plasma-induced-damage of GaAs during etching of refractory metal contacts
- Sandia National Labs., Albuquerque, NM (United States)
- Univ. of Florida, Gainesville, FL (United States)
The effect of plasma-induced-damage on the majority carrier transport properties of GaAs has been studied by monitoring changes in sheet resistance (R{sub s}) of thin conducting layers under various plasma conditions including etch conditions for refractory metal contacts. R{sub s} determined from transmission line measurements are used to evaluate plasma-induced-damage for electron cyclotron resonance (ECR) and reactive ion etch (RIE) conditions by varying the thickness of doped epitaxial layers. The authors speculate that plasma-induced-damage in the near surface region plays a major role in explaining the damage mechanism observed in this study. Very consistent trends have been observed where R{sub s} increases with increasing ECR and RIE dc-bias, increasing microwave power, and decreasing pressure, thus showing R{sub s} increases as either the ion energy or ion flux increases. The authors have also observed that R{sub s} is lower for samples exposed to the RIE than the ECR, possibly due to higher ion and electron densities generated in the ECR and higher pressures in the RIE. It has also been observed R{sub s} dependence on ECR plasma chemistry where, R{sub s} is lower in SF{sub 6}/Ar plasmas than Ar and N{sub 2} plasmas possibly related to interactions of F or S atoms with the GaAs surface. Moderate anneal temperatures (200 to 500{degrees}C) have shown significant R{sub s} recovery.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 10189619
- Report Number(s):
- SAND--94-1318C; CONF-941001--1; ON: DE95001525
- Country of Publication:
- United States
- Language:
- English
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