C. Process parameters

C.1 Cleaning process

C.1.0.1 Cleaning before photo-lithography

$\parbox{\textwidth}{\small \begin{itemize} \item immersion (with ... ...ot plate drying, $170^\circ$C, 5 min \item visual inspection. \end{itemize}}$

C.1.0.2 Cleaning before metallization: deoxidation of GaAs

$\parbox{\textwidth}{\small \begin{itemize} \item immersion in HCl... ...se in deionized (DI) water, 2 min \item nitrogen blow drying. \end{itemize}}$

C.1.0.3 Plasma cleaning after photo-lithography

$\parbox{\textwidth}{\small \begin{itemize} \item Oxygen plasma et... ...~W \item time 20~s \end{itemize} \item visual inspection. \end{itemize}}$

C.1.0.4 Resist removal after etch process

$\parbox{\textwidth}{\small \begin{itemize} \item immersion (with ... ..., 1 min \item nitrogen blow drying \item visual inspection. \end{itemize}}$

C.1.0.5 ECR-Chamber cleaning before plasma-etch

$\parbox{\textwidth}{ \begin{itemize} \item ECR-Chamber cleaning S... ... 14~ml/min cooling circuit \item time 20~min \end{itemize} \end{itemize}}$

$\parbox{\textwidth}{ \begin{itemize} \item ECR-Chamber cleaning S... ... 14~ml/min cooling circuit \item time 10~min \end{itemize} \end{itemize}}$

C.2 Lithography processes

C.2.0.1 Edge removal - lacquering AZ 5214

$\parbox{\textwidth}{ \begin{itemize} \item exposure UV 365 / 7 mW... ...1), 45 s \item rinse in DI water \item nitrogen blow drying \end{itemize}}$

C.2.0.2 Positive process - lacquering AZ 5214

$\parbox{\textwidth}{ \begin{itemize} \item \textit{optional:} adh... ... 45-50~s \item rinse in DI water \item nitrogen blow drying \end{itemize}}$

C.2.0.3 Positive process - lacquering AZ 4564, resist layer for plating air-bridges

$\parbox{\textwidth}{ \begin{itemize} \item AZ 45644 resist spinni... ...gen blow drying \item post bake in oven, $100^\circ$C, 30 min \end{itemize}}$

C.2.0.4 Image-reversal process - lacquering AZ 5214, simple resist layer

$\parbox{\textwidth}{ \begin{itemize} \item AZ 5214 resist spinnin... ...1), 23 s \item rinse in DI water \item nitrogen blow drying \end{itemize}}$

C.2.0.5 Negative process - lacquering PMMA for E-Beam lithography

$\parbox{\textwidth}{ \small \begin{itemize} \item PMMA 600 resist... ...5, 150 s \item rinse in propanol \item nitrogen blow drying \end{itemize}}$

C.2.0.6 Image-reversal process - lacquering AZ 5214, double resist layer

$\parbox{\textwidth}{ \begin{itemize} \item AZ 5214 resist spinnin... ...1), 26 s \item rinse in DI water \item nitrogen blow drying \end{itemize}}$

C.2.0.7 Negative process - lacquering Polyamide (Durimide 7510)

$\parbox{\textwidth}{ \hspace{1cm} \textbf{Lithography} \begin{item... ...tem development stop in 2-propanol \item nitrogen blow drying \end{itemize}}$

$\parbox{\textwidth}{ \hspace{1cm} \textbf{Polyamide hardening in va... ...irc$C, slope $-150^\circ$C/h \item oven with nitrogen venting \end{itemize}}$

C.3 Wet-chemical etching processes

C.3.0.1 GaAs etching with sulfuric acid for substrate removal

$\parbox{\textwidth}{ \small \begin{itemize} \item H$_2$SO$_4$\ : ... ...m/min}$ \item rinse in DI water, \item nitrogen blow drying \end{itemize}}$

C.3.0.2 GaAs etching with sulfuric acid for mesa isolation

$\parbox{\textwidth}{\small \begin{itemize} \item H$_2$SO$_4$\ : H... ...m/min}$ \item rinse in DI water, \item nitrogen blow drying \end{itemize}}$

C.3.0.3 Selective Etching of GaAs over $Al_{0.6}Ga_{0.4}As$

$\parbox{\textwidth}{\small \begin{itemize} \item C$_6$H$_8$O$_7$\... ...m/min}$ \item rinse in DI water, \item nitrogen blow drying \end{itemize}}$

C.3.0.4 Selective Etching of $Al_{0.6}Ga_{0.4}As$ over GaAs

$\parbox{\textwidth}{\small \begin{itemize} \item HF (48\%) : H$_2... ...I water \item rinse in DI water, \item nitrogen blow drying \end{itemize}}$

C.3.0.5 Etching process for nickel removal

$\parbox{\textwidth}{\small \begin{itemize} \item 5 g FeCl$_3$\ : ... ...\ 4 min \item rinse in DI water, \item nitrogen blow drying \end{itemize}}$

C.3.0.6 Etching process for titan removal

$\parbox{\textwidth}{ \small \begin{itemize} \item AF 91-9 [(NH$_4... ...tation) \item rinse in DI water, \item nitrogen blow drying \end{itemize}}$

C.4 Plasma-etching processes

C.4.0.1 ECR-RIE process for GaAs, AlGaAs mesas

$\parbox{\textwidth}{\small \begin{itemize} \item Cl$_2$\ flux 8~m... ...item cooling $0^\circ$C, with He flow 14~ml/min cooling circuit \end{itemize}}$

C.4.0.2 ECR-RIE process for GaN mesas

$\parbox{\textwidth}{\small \begin{itemize} \item Cl$_2$\ flux 20~... ...item cooling $2^\circ$C, with He flow 14~ml/min cooling circuit \end{itemize}}$

C.4.0.3 ECR-RIE process for GaN nanocolumns

$\parbox{\textwidth}{\small \begin{itemize} \item Cl$_2$\ flux 16~... ...n cooling circuit \item (optional) 1 min RF on / 1 min RF off \end{itemize}}$

C.4.0.4 RIE process for Polyimide (Durimide 7510)

$\parbox{\textwidth}{ \small \begin{itemize} \item O$_2$-Flus 30~m... ...us 1~ml/min \item process pressure 1 mbar \item power 100~W \end{itemize}}$

C.5 Metallization processes

C.5.0.1 Ohmic contacts (for GaAs)

$\parbox{\textwidth}{\small \begin{itemize} \item 20 nm Ge / 15 nm Ni / 200 nm Au \end{itemize}}$

C.5.0.2 Ohmic contacts (for GaN)

$\parbox{\textwidth}{\small \begin{itemize} \item 35 nm Ti / 200 nm Al / 50 Ni / 200 nm Au \end{itemize}}$

C.5.0.3 Bond pads

$\parbox{\textwidth}{\small \begin{itemize} \item 30 nm Ti / 600 nm Au, rotating evaporation \end{itemize}}$

C.5.0.4 Bond pads for polyamide process

$\parbox{\textwidth}{\small \begin{itemize} \item 50 nm Ti / 50 nm Au / 50 nm Ti / 650 nm Au, rotating evaporation \end{itemize}}$

C.5.0.5 Air-bridge seed layer

$\parbox{\textwidth}{\small \begin{itemize} \item 1 nm Cr / 90 nm Au \\ or \item 80 nm Au /10 nm Ti \end{itemize}}$

C.5.0.6 Lift-Off process

$\parbox{\textwidth}{\small \begin{itemize} \item immersion (with ... ..., 2 min \item nitrogen blow drying \item visual inspection. \end{itemize}}$

C.5.0.7 Annealing of Ge/Ni/Au metallization in RTP oven

$\parbox{\textwidth}{ \hspace {1cm} \textbf{temperature profile}\sma... ...\item cool down to room temperature, 240 s, N$_2$\ flux 5 l/min \end{itemize}}$

C.5.0.8 Annealing of Ti/Al/Ni/Au metallization in RTP oven

$\parbox{\textwidth}{ \hspace {1cm} \textbf{temperature profile}\sma... ...\item cool down to room temperature, 240 s, N$_2$\ flux 5 l/min \end{itemize}}$

C.5.0.9 Gold galvanic plating

$\parbox{\textwidth}{\small \begin{itemize} \item plating bath prep... ...m/min}$ \item rinse in DI water, \item nitrogen blow drying \end{itemize}}$